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  1. ARM Convective Available Potential Energy (CAPE), Convective...

    Office of Scientific and Technical Information (OSTI)

    Country of Publication: United States Availability: ORNL Language: English Subject: 54 Environmental Sciences ARMBE, Soundings; Convective Available Potential Energy (CAPE); ...

  2. ARM - PI Product - Convective Available Potential Energy (CAPE), Convective

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Inhibition (CIN) Product Products Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product ARM soundings are used to determine Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) and associated properties. Data Details

  3. ARM Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Michael

    2014-04-10

    ARM soundings are used to determine Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) and associated properties, using the following relationships;

  4. ARM Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Michael

    ARM soundings are used to determine Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) and associated properties, using the following relationships;

  5. Assessment of primary production and optical variability in shelf and slope waters near Cape Hatteras, North Carolina. Final project report

    SciTech Connect (OSTI)

    Redalje, Donald G.; Lohrenz, Stevern E.

    2001-02-12

    In this project we determined primary production and optical variability in the shelf and slope waters off of Cape Hatteras, N.C. These processes were addressed in conjunction with other Ocean Margins Program investigators, during the Spring Transition period and during Summer. We found that there were significant differences in measured parameters between Spring and Summer, enabling us to develop seasonally specific carbon production and ecosystem models as well as seasonal and regional algorithm improvements for use in remote sensing applications.

  6. Convection?

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    What is Tropical Convection? A Few of the Phenomena the Scientists are Studying - Madden-Julian Oscillation - Tropical Cyclones - El Niño and La Niña Definitions: - Atmospheric Convection - Equator - Intertropical Convergence Zone (ITCZ) - Monsoon - Ocean-Atmosphere System - Precipitation - Solar Energy - Tropical Cyclone - Tropical Disturbance Related Activity: Why is it Hotter at the Equator? EDUCATION NEWS Year of Tropical Convection With contributions from Hilary Wingert, 4 th grade

  7. The Conforming Virtual Element Method for the convection-diffusion-reaction equation with variable coeffcients.

    SciTech Connect (OSTI)

    Manzini, Gianmarco; Cangiani, Andrea; Sutton, Oliver

    2014-10-02

    This document describes the conforming formulations for virtual element approximation of the convection-reaction-diffusion equation with variable coefficients. Emphasis is given to construction of the projection operators onto polynomial spaces of appropriate order. These projections make it possible the virtual formulation to achieve any order of accuracy. We present the construction of the internal and the external formulation. The difference between the two is in the way the projection operators act on the derivatives (laplacian, gradient) of the partial differential equation. For the diffusive regime we prove the well-posedness of the external formulation and we derive an estimate of the approximation error in the H1-norm. For the convection-dominated case, the streamline diffusion stabilization (aka SUPG) is also discussed.

  8. Large-scale Environmental Variables and Transition to Deep Convection in Cloud Resolving Model Simulations: A Vector Representation

    SciTech Connect (OSTI)

    Hagos, Samson M.; Leung, Lai-Yung R.

    2012-11-01

    Cloud resolving model simulations and vector analysis are used to develop a quantitative method of assessing regional variations in the relationships between various large-scale environmental variables and the transition to deep convection. Results of the CRM simulations from three tropical regions are used to cluster environmental conditions under which transition to deep convection does and does not take place. Projections of the large-scale environmental variables on the difference between these two clusters are used to quantify the roles of these variables in the transition to deep convection. While the transition to deep convection is most sensitive to moisture and vertical velocity perturbations, the details of the profiles of the anomalies vary from region to region. In comparison, the transition to deep convection is found to be much less sensitive to temperature anomalies over all three regions. The vector formulation presented in this study represents a simple general framework for quantifying various aspects of how the transition to deep convection is sensitive to environmental conditions.

  9. Variability of radiatively forced diurnal cycle of intense convection in the tropical west pacific

    SciTech Connect (OSTI)

    Gray, W.M.; Sheaffer, J.D.; Thorson, W.B.

    1996-04-01

    Strong differences occur in daytime versus nighttime (DVN) net radiative cooling in clear versus cloudy areas of the tropical atmosphere. Daytime average cooling is approximately -0.7{degrees}C/day, whereas nighttime net tropospheric cooling rates are about -1.5{degrees}C/day, an approximately two-to-one difference. The comparatively strong nocturnal cooling in clear areas gives rise to a diurnally varying vertical circulation and horizontal convergence cycle. Various manifestations of this cyclic process include the observed early morning heavy rainfall maxima over the tropical oceans. The radiatively driven DVN circulation appears to strongly modulate the resulting diurnal cycle of intense convection which creates the highest, coldest cloudiness over maritime tropical areas and is likely a fundamental mechanism governing both small and large scale dynamics over much of the tropical environment.

  10. Cape Wind Project | Open Energy Information

    Open Energy Info (EERE)

    Project Jump to: navigation, search Name Cape Wind Project Facility Cape Wind Sector Wind energy Facility Type Offshore wind Facility Status Proposed Owner Cape Wind Developer Cape...

  11. Sensitivity of MJO to the CAPE lapse time in the NCAR CAM3

    SciTech Connect (OSTI)

    LIU, P.; Wang, B.; Meehl, Gerald, A.

    2007-09-05

    Weak and irregular boreal winter MJO in the NCAR CAM3 corresponds to very low CAPE background, which is caused by easy-to-occur and over-dominant deep convection indicating the deep convective scheme uses either too low CAPE threshold as triggering function or too large consumption rate of CAPE to close the scheme. Raising the CAPE threshold from default 70 J/kg to ten times large only enhances the CAPE background while fails to noticeably improve the wind mean state and the MJO. However, lengthening the CAPE lapse time from one to eight hours significantly improved the background in CAPE and winds, and salient features of the MJO. Variances, dominant periods and zonal wave numbers, power spectra and coherent propagating structure in winds and convection associated with MJO are ameliorated and comparable to the observations. Lengthening the CAPE lapse time to eight hours reduces dramatically the cloud base mass flux, which prevents effectively the deep convection from occurring prematurely. In this case, partitioning of deep to shallow convection in MJO active area is about 5:4.5 compared to over 9:0.5 in the control run. Latent heat is significantly enhanced below 600 hPa over the central Indian Ocean and the western Pacific. Such partitioning of deep and shallow convection is argued necessary for simulating realistic MJO features. Although the universal eight hours lies in the upper limit of that required by the quasi-equilibrium theory, a local CAPE lapse time for the parameterized cumulus convection will be more realistic.

  12. Numerical investigation of CO{sub 2} emission and thermal stability of a convective and radiative stockpile of reactive material in a cylindrical pipe of variable thermal conductivity

    SciTech Connect (OSTI)

    Lebelo, Ramoshweu Solomon

    2014-10-24

    In this paper the CO{sub 2} emission and thermal stability in a long cylindrical pipe of combustible reactive material with variable thermal conductivity are investigated. It is assumed that the cylindrical pipe loses heat by both convection and radiation at the surface. The nonlinear differential equations governing the problem are tackled numerically using Runge-Kutta-Fehlberg method coupled with shooting technique method. The effects of various thermophysical parameters on the temperature and carbon dioxide fields, together with critical conditions for thermal ignition are illustrated and discussed quantitatively.

  13. University of Cape Town | Open Energy Information

    Open Energy Info (EERE)

    to: navigation, search Name: University of Cape Town Place: South Africa Product: Teaching and research university. References: University of Cape Town1 This article is a...

  14. Resolution-dependent behavior of subgrid-scale vertical transport in the Zhang-McFarlane convection parameterization

    SciTech Connect (OSTI)

    Xiao, Heng; Gustafson, William I.; Hagos, Samson M.; Wu, Chien-Ming; Wan, Hui

    2015-06-01

    To better understand the behavior of quasi-equilibrium based convective parameterizations at higher resolution, we use a diagnostic frame- work to examine the resolution-dependence of sub grid-scale vertical trans-port of moist static energy as parameterized by the Zhang-McFarlane convection parameterization (ZM). Grid-scale input to ZM is supplied by coarsening output from cloud resolving model (CRM) simulations onto sub-domains ranging in size from 8 _ 8 to 256 _ 256 km2. Then the ZM based parameterization of vertical transport of moist static energy for scales smaller than the sub-domain size (w0h0 ZM) are compared to those directly calculated from the CRM simulations (w0h0CRM) for different sub-domain sizes. The overall strength of w0h0CRM decreases by more than half as the sub-domain size decreases from 128 to 8 km across while w0h0 ZM decreases with sub-domain size only for strong convection cases and increases for weaker cases. The resolution dependence of w0h0 ZM is determined by the positive-denite change rate of grid-scale convective available potential energy (CAPE) in the convective quasi-equilibrium (QE) closure. Further analysis shows the change rate of actual grid-scale CAPE (before taking the positive definite value) and w0h0CRM behave very similarly as the sub-domain size changes because they are both tied to grid-scale advective tendencies. We can improve the resolution dependence of w0h0ZM significantly by averaging the grid-scale change rate of CAPE over an appropriately large area surrounding each sub-domain before taking its positive definite value. Even though the overall strength of w0h0CRM decreases with increasing resolution, its variability increases dramatically. w0h0ZM can capture neither the magnitude nor the pattern of this variability at relatively high resolutions (8 or 16 km grid spacing), suggesting the need for stochastic treatment of convection at these scales.

  15. EIS-0470: Cape Wind Energy Project, Nantucket Sound, Offshore...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    0: Cape Wind Energy Project, Nantucket Sound, Offshore of Massachusetts EIS-0470: Cape Wind Energy Project, Nantucket Sound, Offshore of Massachusetts EIS-0470: Cape Wind Energy ...

  16. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L.

    1995-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  17. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L.

    1994-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode.

  18. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L.

    1996-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  19. Convection towers

    DOE Patents [OSTI]

    Prueitt, M.L.

    1996-01-16

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water. 6 figs.

  20. Reactor Engineering: Experimental Investigation of Alpha Convection

    SciTech Connect (OSTI)

    Usman, Shoaib

    2012-10-12

    Natural convection, Rayleigh-Bernard convection, Transient convection and Conduction convection transition.

  1. Convection towers

    DOE Patents [OSTI]

    Prueitt, M.L.

    1994-02-08

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode. 5 figures.

  2. CONVECTION REACTOR

    DOE Patents [OSTI]

    Hammond, R.P.; King, L.D.P.

    1960-03-22

    An homogeneous nuclear power reactor utilizing convection circulation of the liquid fuel is proposed. The reactor has an internal heat exchanger looated in the same pressure vessel as the critical assembly, thereby eliminating necessity for handling the hot liquid fuel outside the reactor pressure vessel during normal operation. The liquid fuel used in this reactor eliminates the necessity for extensive radiolytic gas rocombination apparatus, and the reactor is resiliently pressurized and, without any movable mechanical apparatus, automatically regulates itself to the condition of criticality during moderate variations in temperature snd pressure and shuts itself down as the pressure exceeds a predetermined safe operating value.

  3. Convective heater

    DOE Patents [OSTI]

    Thorogood, Robert M.

    1986-01-01

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

  4. Convective heater

    DOE Patents [OSTI]

    Thorogood, Robert M.

    1983-01-01

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

  5. Convective heater

    DOE Patents [OSTI]

    Thorogood, R.M.

    1983-12-27

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation. 14 figs.

  6. Cape Verde Capital | Open Energy Information

    Open Energy Info (EERE)

    Capital Jump to: navigation, search Name: Cape Verde Capital Place: Leatherhead, United Kingdom Zip: KT22 7SW Sector: Renewable Energy Product: The renewable energy investment arm...

  7. Cape Systems Limited | Open Energy Information

    Open Energy Info (EERE)

    Limited Jump to: navigation, search Name: Cape Systems Limited Place: Rock Sound, Bahamas Sector: Services Product: Offers installation and site surveying services for clean...

  8. Cape Cod Regional Transit Authority | Open Energy Information

    Open Energy Info (EERE)

    Cod Regional Transit Authority Jump to: navigation, search Name Cape Cod Regional Transit Authority Facility Cape Cod Regional Transit Authority Sector Wind energy Facility Type...

  9. DOE Offers Conditional Commitment to Cape Wind Offshore Wind...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Offers Conditional Commitment to Cape Wind Offshore Wind Generation Project DOE Offers Conditional Commitment to Cape Wind Offshore Wind Generation Project September 11, 2014 - ...

  10. EIS-0470: Cape Wind Energy Project, Nantucket Sound, Offshore of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Massachusetts | Department of Energy 0: Cape Wind Energy Project, Nantucket Sound, Offshore of Massachusetts EIS-0470: Cape Wind Energy Project, Nantucket Sound, Offshore of Massachusetts June 25, 2014 EIS-0470: Cape Wind Energy Project, Final General Conformity Determination Cape Wind Energy Project, Final General Conformity Determination, June 23, 2014 December 21, 2012 EIS-0470: Final Environmental Impact Statement Cape Wind Energy Project, Nantucket Sound, MA December 31, 2012 EIS-0470:

  11. Cape Wind Associates LLC | Open Energy Information

    Open Energy Info (EERE)

    is developing an offshore wind farm off the coast of Cape Cod in Massachussets, USA. Coordinates: 42.358635, -71.056699 Show Map Loading map... "minzoom":false,"mappi...

  12. Cape Verde: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Country Profile Name Cape Verde Population 512,096 GDP 2,071,000,000 Energy Consumption 0.00 Quadrillion Btu 2-letter ISO code CV 3-letter ISO code CPV Numeric ISO...

  13. West Cape May, New Jersey: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Hide Map This article is a stub. You can help OpenEI by expanding it. West Cape May is a borough in Cape May County, New Jersey. It falls under New Jersey's 2nd...

  14. Convective Radio Occultations Campaign

    Office of Scientific and Technical Information (OSTI)

    The intensity forecast and monitoring of convective systems is one of the major challenges ... measurements in combination with atmospheric profiles from Global Positioning System ...

  15. Porcess-industry CAPE-OPEN software standard overview

    SciTech Connect (OSTI)

    Zitney, S.

    2009-01-01

    CAPE-OPEN (CAPE is short for Computer Aided Process Engineering) is a standard for writing computer software interfaces. It is mainly applied in process engineering where it enables a standardized communication between process simulators (e.g. Aspen Plus) and products developed by ourselves. The advantage of CAPE-OPEN is that these products are applicable to more than just one process simulator; they are aimed at all process simulators that are CAPE-OPEN compliant.

  16. DOE Offers Conditional Commitment to Cape Wind Offshore Wind Generation

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Project | Department of Energy Offers Conditional Commitment to Cape Wind Offshore Wind Generation Project DOE Offers Conditional Commitment to Cape Wind Offshore Wind Generation Project September 11, 2014 - 3:26pm Addthis The U.S. Department of Energy (DOE) recently announced the first step toward issuing a $150 million loan guarantee to support the construction of the Cape Wind offshore wind project with a conditional commitment to Cape Wind Associates, LLC. The project could be the first

  17. Interactions between cumulus convection and its environment as revealed by the MC3E sounding array

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xie, Shaocheng; Zhang, Yunyan; Giangrande, Scott E.; Jensen, Michael P.; McCoy, Renata; Zhang, Minghua

    2014-10-27

    This study attempts to understand interactions between midlatitude convective systems and their environments through a heat and moisture budget analysis using the sounding data collected from the Midlatitude Continental Convective Clouds Experiment (MC3E) in central Oklahoma. Distinct large-scale structures and diabatic heating and drying profiles are presented for cases of weaker and elevated thunderstorms as well as intense squall line and supercell thunderstorm events during the campaign. The elevated cell events were nocturnal convective systems occurring in an environment having low convective available potential energy (CAPE) and a very dry boundary layer. In contrast, deeper convective events happened during themore » morning into early afternoon within an environment associated with large CAPE and a near-saturated boundary layer. As the systems reached maturity, the diagnosed diabatic heating in the latter deep convective cases was much stronger and of greater vertical extent than the former. Both groups showed considerable diabatic cooling in the lower troposphere, associated with the evaporation of precipitation and low-level clouds. The horizontal advection of moisture also played a dominant role in moistening the lower troposphere, particularly for the deeper convective events, wherein the near surface southeasterly flow allows persistent low-level moisture return from the Gulf of Mexico to support convection. The moisture convergence often was present before these systems develop, suggesting a strong correlation between the large-scale moisture convergence and convection. As a result, sensitivity tests indicated that the uncertainty in the surface precipitation and the size of analysis domain mainly affected the magnitude of these analyzed fields rather than their vertical structures.« less

  18. ARM - Measurement - Convection

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    govMeasurementsConvection ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Convection Vertical motion within the atmosphere due to thermal instability, with important impacts on the type cloud systems that can develop. Categories Atmospheric State Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each

  19. ARM - News from the Cape Cod Deployment

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    News from the Cape Cod Deployment Related Links TCAP Home Outreach News & Press WCAI Interview with Dr. Berg (YouTube) Frequently Asked Questions Brochure Backgrounder (PDF, 1.5MB) AMF Poster, 2012 Images ARM flickr site ARM Data Discovery Browse Data Deployment Operations Data Sets Baseline Instruments and Data Plots at the Archive Airborne Measurements Airborne Data Sets Science Plan (PDF, 1.6 MB) G-1 Cabin Layout TCAP wiki Login Required Experiment Planning Proposal Abstract and Related

  20. Cape May Court House, New Jersey: Energy Resources | Open Energy...

    Open Energy Info (EERE)

    County, New Jersey.1 Registered Energy Companies in Cape May Court House, New Jersey Cap May County Municipal Utilities Authority References US Census Bureau 2005 Place to...

  1. Cape May County, New Jersey: Energy Resources | Open Energy Informatio...

    Open Energy Info (EERE)

    4 Climate Zone Subtype A. Registered Energy Companies in Cape May County, New Jersey Cap May County Municipal Utilities Authority Fishermen s Energy Fishermen s Energy of New...

  2. Cape Verde Archipelago Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Energy, Wind Topics Finance, Market analysis, Background analysis Website http:www.europa-eu-un.orgar Program Start 2010 Country Cape Verde UN Region Western Africa References...

  3. Cape Girardeau County, Missouri: Energy Resources | Open Energy...

    Open Energy Info (EERE)

    Cape Girardeau, Missouri Delta, Missouri Dutchtown, Missouri Gordonville, Missouri Jackson, Missouri Oak Ridge, Missouri Old Appleton, Missouri Pocahontas, Missouri Scott City,...

  4. Cape Light Compact- Residential Energy Efficiency Rebate Program

    Broader source: Energy.gov [DOE]

    Cape Light Compact (CLC) offers a variety of financial incentives to customers for purchasing energy efficient residential equipment. Residential customers can take advantage of incentives on...

  5. Cape Town, South Africa: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Systems Registered Energy Companies in Cape Town, South Africa Atlantic Solar Genesis Eco Energy Mulilo Renewable Energy Pty Ltd SetSolar References http:www.geonames.org...

  6. Cape Peninsula University of Technology - Centre for Distributed...

    Open Energy Info (EERE)

    Power and Electronic Systems is a research institution based in Cape Town, South Africa. References "Dr Atanda Raji" "Prof. Kahn MTE" "Dr Marco Adonis" "Dr...

  7. Convective Radio Occultations Final Campaign Summary (Technical...

    Office of Scientific and Technical Information (OSTI)

    Convective Radio Occultations Final Campaign Summary Citation Details In-Document Search Title: Convective Radio Occultations Final Campaign Summary Deep convective systems are ...

  8. Cape Coral Youth Center Helps Light the Way to Energy Savings | Department

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    of Energy Cape Coral Youth Center Helps Light the Way to Energy Savings Cape Coral Youth Center Helps Light the Way to Energy Savings May 18, 2011 - 4:32pm Addthis Cape Coral Youth Center Manager Mark Cagel stands in front of a tamper-proof thermostat at the Austen Youth Center in Cape Coral, Florida. | Photo Courtesy of the Cape Coral Youth Center Cape Coral Youth Center Manager Mark Cagel stands in front of a tamper-proof thermostat at the Austen Youth Center in Cape Coral, Florida. |

  9. Parameterizing deep convection using the assumed probability density function method

    SciTech Connect (OSTI)

    Storer, R. L.; Griffin, B. M.; Hoft, Jan; Weber, J. K.; Raut, E.; Larson, Vincent E.; Wang, Minghuai; Rasch, Philip J.

    2015-01-06

    Due to their coarse horizontal resolution, present-day climate models must parameterize deep convection. This paper presents single-column simulations of deep convection using a probability density function (PDF) parameterization. The PDF parameterization predicts the PDF of subgrid variability of turbulence, clouds, and hydrometeors. That variability is interfaced to a prognostic microphysics scheme using a Monte Carlo sampling method.The PDF parameterization is used to simulate tropical deep convection, the transition from shallow to deep convection over land, and mid-latitude deep convection.These parameterized single-column simulations are compared with 3-D reference simulations. The agreement is satisfactory except when the convective forcing is weak. The same PDF parameterization is also used to simulate shallow cumulus and stratocumulus layers. The PDF method is sufficiently general to adequately simulate these five deep, shallow, and stratiform cloud cases with a single equation set. This raises hopes that it may be possible in the future, with further refinements at coarse time step and grid spacing, to parameterize all cloud types in a large-scale model in a unified way.

  10. Parameterizing deep convection using the assumed probability density function method

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Storer, R. L.; Griffin, B. M.; Hft, J.; Weber, J. K.; Raut, E.; Larson, V. E.; Wang, M.; Rasch, P. J.

    2015-01-06

    Due to their coarse horizontal resolution, present-day climate models must parameterize deep convection. This paper presents single-column simulations of deep convection using a probability density function (PDF) parameterization. The PDF parameterization predicts the PDF of subgrid variability of turbulence, clouds, and hydrometeors. That variability is interfaced to a prognostic microphysics scheme using a Monte Carlo sampling method.The PDF parameterization is used to simulate tropical deep convection, the transition from shallow to deep convection over land, and midlatitude deep convection. These parameterized single-column simulations are compared with 3-D reference simulations. The agreement is satisfactory except when the convective forcing is weak.moreThe same PDF parameterization is also used to simulate shallow cumulus and stratocumulus layers. The PDF method is sufficiently general to adequately simulate these five deep, shallow, and stratiform cloud cases with a single equation set. This raises hopes that it may be possible in the future, with further refinements at coarse time step and grid spacing, to parameterize all cloud types in a large-scale model in a unified way.less

  11. Parameterizing deep convection using the assumed probability density function method

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Storer, R. L.; Griffin, B. M.; Höft, J.; Weber, J. K.; Raut, E.; Larson, V. E.; Wang, M.; Rasch, P. J.

    2015-01-06

    Due to their coarse horizontal resolution, present-day climate models must parameterize deep convection. This paper presents single-column simulations of deep convection using a probability density function (PDF) parameterization. The PDF parameterization predicts the PDF of subgrid variability of turbulence, clouds, and hydrometeors. That variability is interfaced to a prognostic microphysics scheme using a Monte Carlo sampling method. The PDF parameterization is used to simulate tropical deep convection, the transition from shallow to deep convection over land, and midlatitude deep convection. These parameterized single-column simulations are compared with 3-D reference simulations. The agreement is satisfactory except when the convective forcing ismore » weak. The same PDF parameterization is also used to simulate shallow cumulus and stratocumulus layers. The PDF method is sufficiently general to adequately simulate these five deep, shallow, and stratiform cloud cases with a single equation set. This raises hopes that it may be possible in the future, with further refinements at coarse time step and grid spacing, to parameterize all cloud types in a large-scale model in a unified way.« less

  12. Parameterizing deep convection using the assumed probability density function method

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Storer, R. L.; Griffin, B. M.; Höft, J.; Weber, J. K.; Raut, E.; Larson, V. E.; Wang, M.; Rasch, P. J.

    2014-06-11

    Due to their coarse horizontal resolution, present-day climate models must parameterize deep convection. This paper presents single-column simulations of deep convection using a probability density function (PDF) parameterization. The PDF parameterization predicts the PDF of subgrid variability of turbulence, clouds, and hydrometeors. That variability is interfaced to a prognostic microphysics scheme using a Monte Carlo sampling method. The PDF parameterization is used to simulate tropical deep convection, the transition from shallow to deep convection over land, and mid-latitude deep convection. These parameterized single-column simulations are compared with 3-D reference simulations. The agreement is satisfactory except when the convective forcing ismore » weak. The same PDF parameterization is also used to simulate shallow cumulus and stratocumulus layers. The PDF method is sufficiently general to adequately simulate these five deep, shallow, and stratiform cloud cases with a single equation set. This raises hopes that it may be possible in the future, with further refinements at coarse time step and grid spacing, to parameterize all cloud types in a large-scale model in a unified way.« less

  13. Cape Light Compact- Commercial Energy Efficiency Rebate Program

    Broader source: Energy.gov [DOE]

    Through a multi-member partnership, Cape Light Compact (CLC) and Mass Save offer a variety of financial incentives for commercial and industrial facilities. Custom rebate options are available for...

  14. For Cape Wind, Summer Breeze Makes Offshore Wind Feel Fine |...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Harsh winds from extreme storms battered Cape Cod this past winter and resulted in power outages across the region, and as summers get warmer, beachgoers rely more and more on ...

  15. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.

    1985-01-01

    Natural convection can provide adequate heat distribution in many situtations that arise in buildings. This is appropriate, for example, in passive solar buildings where some rooms tend to be more strongly solar heated than others or to reduce the number of heating units required in a building. Natural airflow and heat transport through doorways and other internal building apertures is predictable and can be accounted for in the design. The nature of natural convection is described, and a design chart is presented appropriate to a simple, single-doorway situation. Natural convective loops that can occur in buildings are described and a few design guidelines are presented.

  16. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.; Yamaguchi, K.

    1983-01-01

    Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.

  17. Energy Department Offers Conditional Commitment to Cape Wind Offshore Wind Generation Project

    Broader source: Energy.gov [DOE]

    The Department of Energy today announced the first step toward issuing a $150 million loan guarantee to support the construction of the Cape Wind offshore wind project with a conditional commitment to Cape Wind Associates, LLC.

  18. Convective heat flow probe

    DOE Patents [OSTI]

    Dunn, J.C.; Hardee, H.C.; Striker, R.P.

    1984-01-09

    A convective heat flow probe device is provided which measures heat flow and fluid flow magnitude in the formation surrounding a borehole. The probe comprises an elongate housing adapted to be lowered down into the borehole; a plurality of heaters extending along the probe for heating the formation surrounding the borehole; a plurality of temperature sensors arranged around the periphery of the probe for measuring the temperature of the surrounding formation after heating thereof by the heater elements. The temperature sensors and heater elements are mounted in a plurality of separate heater pads which are supported by the housing and which are adapted to be radially expanded into firm engagement with the walls of the borehole. The heat supplied by the heater elements and the temperatures measured by the temperature sensors are monitored and used in providing the desired measurements. The outer peripheral surfaces of the heater pads are configured as segments of a cylinder and form a full cylinder when taken together. A plurality of temperature sensors are located on each pad so as to extend along the length and across the width thereof, with a heating element being located in each pad beneath the temperature sensors. An expansion mechanism driven by a clamping motor provides expansion and retraction of the heater pads and expandable packet-type seals are provided along the probe above and below the heater pads.

  19. Convective heat flow probe

    DOE Patents [OSTI]

    Dunn, James C.; Hardee, Harry C.; Striker, Richard P.

    1985-01-01

    A convective heat flow probe device is provided which measures heat flow and fluid flow magnitude in the formation surrounding a borehole. The probe comprises an elongate housing adapted to be lowered down into the borehole; a plurality of heaters extending along the probe for heating the formation surrounding the borehole; a plurality of temperature sensors arranged around the periphery of the probe for measuring the temperature of the surrounding formation after heating thereof by the heater elements. The temperature sensors and heater elements are mounted in a plurality of separate heater pads which are supported by the housing and which are adapted to be radially expanded into firm engagement with the walls of the borehole. The heat supplied by the heater elements and the temperatures measured by the temperature sensors are monitored and used in providing the desired measurements. The outer peripheral surfaces of the heater pads are configured as segments of a cylinder and form a full cylinder when taken together. A plurality of temperature sensors are located on each pad so as to extend along the length and across the width thereof, with a heating element being located in each pad beneath the temperature sensors. An expansion mechanism driven by a clamping motor provides expansion and retraction of the heater pads and expandable packer-type seals are provided along the probe above and below the heater pads.

  20. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.

    1985-01-01

    Natural convection can provide adequate heat distribution in many situations that arise in buildings. This is appropriate, for example, in passive solar buildings where some rooms tend to be more strongly solar heated than others. Natural convection can also be used to reduce the number of auxiliary heating units required in a building. Natural airflow and heat transport through doorways and other internal building apertures are predictable and can be accounted for in the design. The nature of natural convection is described, and a design chart is presented appropriate to a simple, single-doorway situation. Experimental results are summarized based on the monitoring of 15 passive solar buildings which employ a wide variety of geometrical configurations including natural convective loops.

  1. Thermodynamic properties of mesoscale convective systems observed during BAMEX

    SciTech Connect (OSTI)

    Correia, James; Arritt, R.

    2008-11-01

    Dropsonde observations from the Bow-echo and Mesoscale convective vortex EXperiment (BAMEX) are used to document the spatio-temporal variability of temperature, moisture and wind within mesoscale convective systems (MCSs). Onion type sounding structures are found throughout the stratiform region of MCSs but the temperature and moisture variability is large. Composite soundings were constructed and statistics of thermodynamic variability were generated within each sub-region of the MCS. The calculated air vertical velocity helped identify subsaturated downdrafts. We found that lapse rates within the cold pool varied markedly throughout the MCS. Layered wet bulb potential temperature profiles seem to indicate that air within the lowest several km comes from a variety of source regions. We also found that lapse rate transitions across the 0 C level were more common than isothermal, melting layers. We discuss the implications these findings have and how they can be used to validate future high resolution numerical simulations of MCSs.

  2. ARM - Midlatitude Continental Convective Clouds

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Bartholomew, Mary Jane; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  3. ARM - Midlatitude Continental Convective Clouds

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Bartholomew, Mary Jane; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    2012-01-19

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  4. NATURAL CONVECTION IN ROOM GEOMETRIES

    SciTech Connect (OSTI)

    Gadgil, A.; Bauman, Fred; Kammerud, R.; Ruberg, K.

    1980-06-01

    Computer programs have been developed to numerically simulate natural convection in room geometries in two and three dimensions. The programs have been validated using published data from the literature, results from a full-scale experiment performed at Massachusetts Institute of Technology, and results from a small-scale experiment reported here. One of the computer programs has been used to study the influence of natural convection on the thermal performance of a single thermal zone in a direct-gain passive solar building. The results indicate that the building heating loads calculated by standard building energy analysis methods may be in error by as much as 50% as a result of their use of common assumptions regarding the convection processes which occur in an enclosure. It is also found that the convective heat transfer coefficients between the air and the enclosure surfaces can be substantially different from the values assumed in the standard building energy analysis methods, and can exhibit significant variations across a given surface.

  5. Improving Convective Parameterization Using ARM Data

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Improving Convective Parameterization Using ARM Data G. J. Zhang Center for Atmospheric Sciences Scripps Institution of Oceanography La Jolla, California Introduction Convective parameterization is one of the most challenging issues in global climate models (GCMs). Convection, as represented by convective parameterization schemes in GCMs, is controlled by the large- scale dynamic and thermodynamic fields through a closure condition. Such a closure condition is typically determined empirically by

  6. Midlatitude Continental Convective Clouds Experiment (MC3E)

    SciTech Connect (OSTI)

    Jensen, MP; Petersen, WA; Del Genio, AD; Giangrande, SE; Heymsfield, A; Heymsfield, G; Hou, AY; Kollias, P; Orr, B; Rutledge, SA; Schwaller, MR; Zipser, E

    2010-04-01

    an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors, and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that have never before been available. Several different components of convective cloud and precipitation processes tangible to both the convective parameterization and precipitation retrieval algorithm problem are targeted, such as preconvective environment and convective initiation, updraft/downdraft dynamics, condensate transport and detrainment, precipitation and cloud microphysics, spatial and temporal variability of precipitation, influence on the environment and radiation, and a detailed description of the large-scale forcing.

  7. MHK Projects/Wavemill Energy Cape Breton Island NS CA | Open...

    Open Energy Info (EERE)

    Wavemill Energy Cape Breton Island NS CA < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlem...

  8. DOE Zero Energy Ready Home Case Study: John Hubert Associates, North Cape

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    May, NJ | Department of Energy John Hubert Associates, North Cape May, NJ DOE Zero Energy Ready Home Case Study: John Hubert Associates, North Cape May, NJ DOE Zero Energy Ready Home Case Study: John Hubert Associates, North Cape May, NJ Case study of a DOE Zero Energy Ready home in North Cape May, NJ, that scored a HERS 46 without PV or HERS 9 with 6.5 kW of PV. The two-story, 1,871-ft2 home has advanced-framed above-grade walls with R-21 fiberglass batt plus an R-3.6-insulated coated OSB

  9. Stratiform and Convective Precipitation Observed by Multiple...

    Office of Scientific and Technical Information (OSTI)

    The composite distributions of KAZR reflectivity and Doppler velocity also show two distinct structures for convective and stratiform rain. These indicate that the method produces ...

  10. ARM - Evaluation Product - Convective Vertical Velocity

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    In particular, vertical air motions associated with these processes are inherently linked to the life cycle of these convective systems and are therefore directly tied to their...

  11. ARM - Midlatitude Continental Convective Clouds - Single Column...

    Office of Scientific and Technical Information (OSTI)

    - Single Column Model Forcing (xie-scmforcing) Title: ARM - Midlatitude Continental Convective Clouds - Single Column Model Forcing (xie-scmforcing) The constrained variational ...

  12. Advection, Moistening, and Shallow-to-deep Convection Transitions During the Initiation and Propagation of Madden-Julian Oscillation

    SciTech Connect (OSTI)

    Hagos, Samson M.; Feng, Zhe; Landu, Kiranmayi; Long, Charles N.

    2014-09-11

    Using observations from the 2011 AMIE/DYNAMO field campaign over the Indian Ocean and a high-resolution regional model simulation, the processes that lead to the rapid shallow-to-deep convection transitions associated with the initiation and eastward propagation of the Madden-Julian Oscillation (MJO) are examined. By tracking the evolution of the depth of several thousand individual model simulated precipitation features, the role of and the processes that control the observed midtropospheric moisture buildup ahead of the detection of deep convection are quantified at large and convection scales. The frequency of shallow-to-deep convection transitions is found to be sensitive to this midlevel moisture and large-scale uplift. This uplift along with the decline of large-scale drying by equator-ward advection causes the moisture buildup leading to the initiation of the MJO. Convection scale moisture variability and uplift, and large-scale zonal advection play secondary roles.

  13. Transient Response of a Natural Convection System

    SciTech Connect (OSTI)

    Mohammad, B. S.; Usman, S.; Shoaib, L.; Abdallah, S.

    2006-07-01

    Transient response of a natural convection system is investigated by numerical simulation using FLUENT code. An Integrator Circuit analogy was recently proposed for natural convection system. The proposed analogy was further confirmed by these recent simulations. New simulation results also suggest that a natural convection system acts as a 'Low Pass' filter for transients. Transmission/attenuation characteristics of natural convection system were investigated using a sinusoidal temperature at the source side boundary. Transient transmission/ attenuation factor was found to be a function of both fluid properties and the flow characteristics. Transmission/attenuation factor was also found to be a strong function of fluctuation frequency. These results may prove a significant design tool for Gen IV natural convection system particularly for LFR. (authors)

  14. ARM - Field Campaign - ARM Support for the Plains Elevated Convection...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    govCampaignsARM Support for the Plains Elevated Convection at Night Experiment: Doppler Lidar Operations Related Campaigns ARM Support for the Plains Elevated Convection at Night...

  15. Convectively driven PCR thermal-cycling (Patent) | DOEPatents

    Office of Scientific and Technical Information (OSTI)

    Convectively driven PCR thermal-cycling Title: Convectively driven PCR thermal-cycling A polymerase chain reaction system provides an upper temperature zone and a lower temperature ...

  16. A dual mass flux framework for boundary layer convection

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A dual mass flux framework for boundary layer convection Neggers, Roel European Centre for Medium-range Weather Forecasts (ECMWF) Category: Modeling A new convective boundary layer...

  17. Transient Mixed Convection Validation for NGNP

    SciTech Connect (OSTI)

    Smith, Barton; Schultz, Richard

    2015-10-19

    The results of this project are best described by the papers and dissertations that resulted from the work. They are included in their entirety in this document. They are: (1) Jeff Harris PhD dissertation (focused mainly on forced convection); (2) Blake Lance PhD dissertation (focused mainly on mixed and transient convection). This dissertation is in multi-paper format and includes the article currently submitted and one to be submitted shortly; and, (3) JFE paper on CFD Validation Benchmark for Forced Convection.

  18. Convective heat transfer inside passive solar buildings

    SciTech Connect (OSTI)

    Jones, R.W.; Balcomb, J.D.; Yamaguchi, K.

    1983-11-01

    Natural convection between spaces in a building which play a major role in energy transfer are discussed. Two situations are investigated: Convection through a single doorway into a remote room, and a convective loop in a two story house with a south sunspace where a north stairway serves as the return path. A doorway sizing equation is given for the single door case. Data from airflow monitoring in one two-story house and summary data for five others are presented. The nature of the airflow and design guidelines are presented.

  19. Convective heat transfer inside passive solar buildings

    SciTech Connect (OSTI)

    Jones, R.W.; Balcomb, J.D.; Yamaguchi, K.

    1983-01-01

    Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.

  20. Fuel Cell Demonstration at the U.S. Coast Guard Air Station Cape Cod

    SciTech Connect (OSTI)

    Halverson, Mark A.; Chvala, William D.; Herrera, Shawn

    2005-07-30

    Journal article reporting on the 250-kW fuel cell combined heat and power plant located at the U.S. Coast Guard Air Station Cape Code in Bourne, Massachusetts.

  1. Convective Cooling and Passive Stack Improvements in Motors (Presentation)

    SciTech Connect (OSTI)

    Bennion, K.

    2014-06-01

    This presentation discusses current research at NREL in convective cooling and passive stack improvements in motors.

  2. Atmospheric Radiation Measurement Convective and Orographically Induced

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Convective and Orographically Induced Precipitation Study The U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) Climate Research Facility is providing the ARM Mobile Facility (AMF) to support a long-term precipitation study in the Black Forest region of Germany. Requested by researchers from the University of Hohenheim, the AMF will be deployed as one of four heav- ily instrumented supersites established for the Convective and Orographically Induced Precipita- tion Study

  3. Mixed convection transport from an isolated heat source module on a horizontal plate

    SciTech Connect (OSTI)

    Kang, B.H.; Jaluria, Y.; Tewari, S.S. )

    1990-08-01

    An experimental study of the mixed convective heat transfer from an isolated source of finite thickness, located on a horizontal surface in an externally induced forced flow, has been carried out. This problem is of particular interest in the cooling of electronic components and also in the thermal transport associated with various manufacturing systems, such as ovens and furnaces. The temperature distribution in the flow as well as the surface temperature variation are studied in detail. The dependence of the heat transfer rate on the mixed convection parameter and on the thickness of the heated element or source, particularly in the vicinity of the source, is investigated. The results obtained indicate that the heat transfer rate and fluid flow characteristics vary strongly with the mixed convection variables. The transition from a natural convection dominated flow to a forced convection dominated flow is studied experimentally and the basic characteristics of the two regimes determined. This transition has a strong influence on the temperature of the surface and on the heat transfer rate. As expected, the forced convection dominated flow is seen to be significantly more effective in the cooling of a heat dissipating component than a natural convection dominated flow. The location of the maximum temperature on the module surface, which corresponds to the minimum local heat transfer coefficient, is determined and discussed in terms of the underlying physical mechanisms. The results obtained are also compared with these for an element of negligible thickness and the effect of a significant module thickness on the transport is determined. Several other important aspects of fundamental and applied interest are studied in this investigation.

  4. The Midlatitude Continental Convective Clouds Experiment (MC3E) sounding network: operations, processing and analysis

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jensen, M. P.; Toto, T.; Troyan, D.; Ciesielski, P. E.; Holdridge, D.; Kyrouac, J.; Schatz, J.

    2014-09-12

    The Midlatitude Continental Convective Clouds Experiment (MC3E) took place during the spring of 2011 centered in north-central Oklahoma, USA. The main goal of this field campaign was to capture the dynamical and microphysical characteristics of precipitating convective systems in the Central Plains. A major component of the campaign was a 6-site radiosonde array designed to capture the large-scale variability of the atmospheric state with the intent of deriving model forcing datasets. Over the course of the 46 day MC3E campaign, a total of 1362 radiosondes were launched from the enhanced sonde network. This manuscript describes the details of the instrumentationmore » used as part of the sounding array, the data processing activities including quality checks and humidity bias corrections and an analysis of the impacts of bias correction and algorithm assumptions on the determination of convective levels and indices. It is found that corrections for known radiosonde humidity biases and assumptions regarding the characteristics of the surface convective parcel result in significant differences in the derived values of convective levels and indices in many soundings.« less

  5. The Midlatitude Continental Convective Clouds Experiment (MC3E) sounding network: operations, processing and analysis

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jensen, M. P.; Toto, T.; Troyan, D.; Ciesielski, P. E.; Holdridge, D.; Kyrouac, J.; Schatz, J.; Zhang, Y.; Xie, S.

    2015-01-27

    The Midlatitude Continental Convective Clouds Experiment (MC3E) took place during the spring of 2011 centered in north-central Oklahoma, USA. The main goal of this field campaign was to capture the dynamical and microphysical characteristics of precipitating convective systems in the US Central Plains. A major component of the campaign was a six-site radiosonde array designed to capture the large-scale variability of the atmospheric state with the intent of deriving model forcing data sets. Over the course of the 46-day MC3E campaign, a total of 1362 radiosondes were launched from the enhanced sonde network. This manuscript provides details on the instrumentationmore » used as part of the sounding array, the data processing activities including quality checks and humidity bias corrections and an analysis of the impacts of bias correction and algorithm assumptions on the determination of convective levels and indices. It is found that corrections for known radiosonde humidity biases and assumptions regarding the characteristics of the surface convective parcel result in significant differences in the derived values of convective levels and indices in many soundings. In addition, the impact of including the humidity corrections and quality controls on the thermodynamic profiles that are used in the derivation of a large-scale model forcing data set are investigated. The results show a significant impact on the derived large-scale vertical velocity field illustrating the importance of addressing these humidity biases.« less

  6. Final 2014 Remedial Action Report Project Chariot, Cape Thompson, Alaska

    SciTech Connect (OSTI)

    None, None

    2015-03-01

    This report was prepared to document remedial action (RA) work performed at the former Project Chariot site located near Cape Thompson, Alaska during 2014. The work was managed by the U.S. Army Corps of Engineers (USACE) Alaska District for the U.S. Department of Energy (DOE) Office of Legacy Management (LM). Due to the short field season and the tight barge schedule, all field work was conducted at the site July 6 through September 12, 2014. Excavation activities occurred between July 16 and August 26, 2014. A temporary field camp was constructed at the site prior to excavation activities to accommodate the workers at the remote, uninhabited location. A total of 785.6 tons of petroleum, oil, and lubricants (POL)-contaminated soil was excavated from four former drill sites associated with test holes installed circa 1960. Diesel was used in the drilling process during test hole installations and resulted in impacts to surface and subsurface soils at four of the five sites (no contamination was identified at Test Hole Able). Historic information is not definitive as to the usage for Test Hole X-1; it may have actually been a dump site and not a drill site. In addition to the contaminated soil, the steel test hole casings were decommissioned and associated debris was removed as part of the remedial effort.

  7. CONVECTIVE BABCOCK-LEIGHTON DYNAMO MODELS

    SciTech Connect (OSTI)

    Miesch, Mark S.; Brown, Benjamin P.

    2012-02-20

    We present the first global, three-dimensional simulations of solar/stellar convection that take into account the influence of magnetic flux emergence by means of the Babcock-Leighton (BL) mechanism. We have shown that the inclusion of a BL poloidal source term in a convection simulation can promote cyclic activity in an otherwise steady dynamo. Some cycle properties are reminiscent of solar observations, such as the equatorward propagation of toroidal flux near the base of the convection zone. However, the cycle period in this young sun (rotating three times faster than the solar rate) is very short ({approx}6 months) and it is unclear whether much longer cycles may be achieved within this modeling framework, given the high efficiency of field generation and transport by the convection. Even so, the incorporation of mean-field parameterizations in three-dimensional convection simulations to account for elusive processes such as flux emergence may well prove useful in the future modeling of solar and stellar activity cycles.

  8. The Mechanism of First Raindrops Formation in Deep Convective Clouds

    SciTech Connect (OSTI)

    Khain, Alexander; Prabha, Thara; Benmoshe, Nir; Pandithurai, G.; Ovchinnikov, Mikhail

    2013-08-22

    The formation of first raindrops in deep convective clouds is investigated. A combination of observational data analysis and 2-D and 3-D numerical bin microphysical simulations of deep convective clouds suggests that the first raindrops form at the top of undiluted or slightly diluted cores. It is shown that droplet size distributions in these regions are wider and contain more large droplets than in diluted volumes. The results of the study indicate that the initial raindrop formation is determined by the basic microphysical processes within ascending adiabatic volumes. It allows one to predict the height of the formation of first raindrops considering the processes of nucleation, diffusion growth and collisions. The results obtained in the study explain observational results reported by Freud and Rosenfeld (2012) according to which the height of first raindrop formation depends linearly on the droplet number concentration at cloud base. The results also explain why a simple adiabatic parcel model can reproduce this dependence. The present study provides a physical basis for retrieval algorithms of cloud microphysical properties and aerosol properties using satellites proposed by Rosenfeld et al. ( 2012). The study indicates that the role of mixing and entrainment in the formation of the first raindrops is not of crucial importance. It is also shown that low variability of effective and mean volume radii along horizontal traverses, as regularly observed by in situ measurements, can be simulated by high-resolution cloud models, in which mixing is parameterized by a traditional 1.5 order turbulence closure scheme.

  9. ARM - Midlatitude Continental Convective Clouds (jensen-sonde)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    2012-01-19

    A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment.

  10. Low enthalpy convective system in Western Ohio

    SciTech Connect (OSTI)

    Cannon, M.S.; Tabet, C.A.; Eckstein, Y.

    1980-01-01

    A distinct positive anomaly in the temperatures of the shallow (Pleistocene) aquifers along the Cincinnati-Findlay Arch in Western Ohio coincides with a low geothermal gradient. A conceptual model of convective currents associated with a tensional fault and/or fracture system along the crest of the Arch is suggested as an explanation of the anomaly. Hydrochemical information indicates that various quantities of warmer ground water, with the composition characteristics of deep bedrock aquifers, is present as an admixture in the shallow aquifers. This confirms the conceptual model of convection in fractures.

  11. Geothermal reservoirs in hydrothermal convection systems

    SciTech Connect (OSTI)

    Sorey, M.L.

    1982-01-01

    Geothermal reservoirs commonly exist in hydrothermal convection systems involving fluid circulation downward in areas of recharge and upwards in areas of discharge. Because such reservoirs are not isolated from their surroundings, the nature of thermal and hydrologic connections with the rest of the system may have significant effects on the natural state of the reservoir and on its response to development. Conditions observed at numerous developed and undeveloped geothermal fields are discussed with respect to a basic model of the discharge portion of an active hydrothermal convection system. Effects of reservoir development on surficial discharge of thermal fluid are also delineated.

  12. Convectively driven PCR thermal-cycling

    DOE Patents [OSTI]

    Benett, William J.; Richards, James B.; Milanovich, Fred P.

    2003-07-01

    A polymerase chain reaction system provides an upper temperature zone and a lower temperature zone in a fluid sample. Channels set up convection cells in the fluid sample and move the fluid sample repeatedly through the upper and lower temperature zone creating thermal cycling.

  13. Surface energy fluxes at Central Florida during the convection and precipitation electrification experiment. Final Report

    SciTech Connect (OSTI)

    Nie, D.; Demetriades-shah, T.D.; Kanemasu, E.T.

    1993-04-01

    One of the objectives of CaPE is to better understand the convective process in central and south Florida during the warm season. The energy and moisture exchanges between the surface and the atmosphere are closely related to this process. Some recent studies have shown that the surface energy balance plays an important role in the climatic fields (Shukla and Mintz; Sud and Smith; Sato et. al). Surface energy fluxes and related surface processes such as evapotranspiration and sensible heat transfer directly effect the temperature, humidity, cloud formation and precipitation. For example, mesoscale circulation around a discontinuity in vegetation type were shown to be stronger with wet soil than with dry soil using an evapotranspiration model (Pinty et. al). In order to better describe the processes in the atmosphere at various scales and improve the ability of modeling and predicting weather related events, it is crucial to understand the mechanism of surface energy transfer in relation to atmospheric events. Surface energy flux measurements are required to fully understand the interactions between the atmosphere and the surface.

  14. CAPE-OPEN compliant stochastic modeling and reduced-order model coputation capaability for APECS system. ORIGINAL TITLE: CAPE-OPEN compliant stochastic modeling capability

    SciTech Connect (OSTI)

    Diwekar, U.; Shastri, Y.; Subramanayan, K.; Zitney, S.

    2007-01-01

    APECS (Advanced Process Engineering Co-Simulator) is an integrated software suite that combines the power of process simulation with high-fidelity, computational fluid dynamics (CFD) for improved design, analysis, and optimization of process engineering systems. The APECS system uses commercial process simulation (e.g., Aspen Plus) and CFD (e.g., FLUENT) software integrated with the process-industry standard CAPE-OPEN (CO) interfaces. This breakthrough capability allows engineers to better understand and optimize the fluid mechanics that drive overall power plant performance and efficiency. The focus of this paper is the CAPE-OPEN complaint stochastic modeling and reduced order model computational capability around the APECS system. The usefulness of capabilities is illustrated with coal fired, gasification based, FutureGen power plant simulation. These capabilities are used to generate efficient reduced order models and optimizing model complexities.

  15. Boreal winter MJO teleconnection in the Community Atmosphere Model version 5 with the Unified Convection parameterization

    SciTech Connect (OSTI)

    Yoo, Changhyun; Park, Sungsu; Kim, Daehyun; Yoon, Jin-Ho; Kim, Hye-Mi

    2015-10-15

    The Madden-Julian Oscillation (MJO), the dominant mode of tropical intraseasonal variability, influences weather and climate in the extratropics through atmospheric teleconnection. In this study, two simulations using the Community Atmosphere Model version 5 (CAM5) - one with the default shallow and deep convection schemes and the other with the Unified Convection scheme (UNICON) - are employed to examine the impacts of cumulus parameterizations on the simulation of the boreal wintertime MJO teleconnection in the Northern Hemisphere. We demonstrate that the UNICON substantially improves the MJO teleconnection. When the UNICON is employed, the simulated circulation anomalies associated with the MJO better resemble the observed counterpart, compared to the simulation with the default convection schemes. Quantitatively, the pattern correlation for the 300-hPa geopotential height anomalies between the simulations and observation increases from 0.07 for the default schemes to 0.54 for the UNICON. These circulation anomalies associated with the MJO further help to enhance the surface air temperature and precipitation anomalies over North America, although room for improvement is still evident. Initial value calculations suggest that the realistic MJO teleconnection with the UNICON is not attributed to the changes in the background wind, but primarily to the improved tropical convective heating associated with the MJO.

  16. The Phenix ultimate natural convection test

    SciTech Connect (OSTI)

    Gauthe, P.; Pialla, D.; Tenchine, D.; Vasile, A.; Rochwerger, D.

    2012-07-01

    The French sodium cooled fast reactor Phenix was shut down in 2009 after 35 years of operation. Before decommissioning, a final set of tests were performed by the CEA during 9 months. Several topics were involved such as thermal hydraulics, core physics and fuel behaviour. Among these ultimate experiments, two thermal hydraulic tests were performed: an asymmetrical test consisting in a trip of one secondary pump and a natural convection test in the primary circuit. Recognizing the unique opportunity offered by these Phenix ultimate tests, IAEA decided in 2007 to launch a Coordinated Research Project (CRP) devoted to benchmarking analyses with system codes on the Phenix natural convection test. One objective of the natural convection test in Phenix reactor is the assessment of the CATHARE system code for safety studies on future and advanced sodium cooled fast reactors. The aim of this paper is to describe this test, which was performed on June 22-23, 2009, and the associated benchmark specifications for the CRP work. The paper reminds briefly the Phenix reactor with the main physical parameters and the instrumentation used during the natural convection test. After that, the test scenario is described: - initial state at a power of 120 MWth, - test beginning resulting from a manual dry out of the two steam generators, - manual scram, - manual trip on the three primary pumps without back-up by pony motors, - setting and development of natural convection in the primary circuit, in a first phase without significant heat sink in the secondary circuits and in a second phase with significant heat sink in the secondary circuits, by opening the casing of steam generators to create an efficient heat sink, by air natural circulation in the steam generators casing. The benchmark case ends after this second phase, which corresponds to the experimental test duration of nearly 7 hours. The paper presents also the benchmark specifications data supplied by the CEA to all

  17. DOE Zero Energy Ready Home Case Study: John Hubert Associates, North Cape May, NJ

    Broader source: Energy.gov [DOE]

    Case study of a DOE Zero Energy Ready home in North Cape May, NJ, that scored a HERS 46 without PV or HERS 9 with 6.5 kW of PV. The two-story, 1,871-ft2 home has advanced-framed above-grade walls...

  18. EECBG Success Story: Cape Coral Youth Center Helps Light the Way to Energy Savings

    Broader source: Energy.gov [DOE]

    The city of Cape Coral, Florida -- a town of located on the coast of the Gulf of Mexico -- is using funding from the Energy Efficiency and Conservation Block Grant (EECBG) program to help reduce the city’s energy use by 40% over the next 15 years. Learn more.

  19. Midlatitude Continental Convective Clouds Experiment Science Objective

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Midlatitude Continental Convective Clouds Experiment Science Objective Despite improvements in computing power, current weather and climate models are unable to accurately reproduce the formation, growth, and decay of clouds and precipitation associated with storm systems. Not only is this due to a lack of data about precipitation, but also about the 3-dimensional environment of the surrounding clouds, winds, and moisture, and how that affects the transfer of energy between the sun and Earth. To

  20. Patterns of Convection in the Tropical Western Pacific

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Patterns of Convection in the Tropical Western Pacific J. H. Mather Pacific Northwest National Laboratory Richland, Washington Introduction Convection is ubiquitous throughout the maritime continent region. However, the frequency of convec- tion is not uniform. While much of this region does not experience seasons to the same degree as one finds in mid-latitudes, the annual cycle of the sun's passage does have a large impact on convection throughout the maritime continent and the tropical

  1. ARM - Field Campaign - Midlatitude Continental Convective Clouds Experiment

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    (MC3E) Experiment (MC3E) Campaign Links Science Plan MC3E Website Field Campaign Report ARM Data Discovery Browse Data Related Campaigns Midlatitude Continental Convective Clouds Experiment (MC3E): Inner Domain Thermodynamic Profiling during MC3E 2011.04.22, Turner, SGP Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers 2011.04.22, Williams, SGP Midlatitude Continental Convective Clouds Experiment: 2DVD Support 2011.04.22, Schwaller, SGP Midlatitude

  2. Limiting Factors for Convective Cloud Top Height in the Tropics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Limiting Factors for Convective Cloud Top Height in the Tropics M. P. Jensen and A. D. Del Genio National Aeronautics and Space Administration Goddard Institute for Space Studies Columbia University New York, New York Introduction Populations of tropical convective clouds are mainly comprised of three types: shallow trade cumulus, mid-level cumulus congestus and deep convective clouds (Johnson et al. 1999). Each of these cloud types has different impacts on the local radiation and water budgets.

  3. Natural convection airflow measurement and theory

    SciTech Connect (OSTI)

    Balcomb, J.D.; Jones, G.F.; Yamaguchi, Kenjiro

    1984-01-01

    Natural convection is a major mechanism for heat distribution in many passive solar buildings, especially those with sunspaces. To better understand this mechanism, observations of air velocities and temperatures have been made in 13 different houses that encompass a wide variety of one- and two-story geometries. This paper extends previous reports. Results from one house are described in detail, and some generalizations are drawn from the large additional mass of data taken. A simple mathematical model is presented that describes the general nature of airflow and energy flow through an aperture.

  4. Title: Radar-observed convective characteristics during TWP-ICE

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    will describe the convective systems observed during the project by two scanning C-band Doppler radars, one of which will provide dual-polarization measurements, and ARM's...

  5. Intercomparison of methods of coupling between convection and...

    Office of Scientific and Technical Information (OSTI)

    defined with profiles obtained from the same model in radiative-convective equilibrium. ... a dry troposphere, DGW simulations always result in a precipitating equilibrium state. ...

  6. Using Cloud-Resolving Model Simulations of Deep Convection to...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    so extending them to a global model with many different environments is not straightforward. For example, deep convection creates abundant cloudiness and yet little is known...

  7. Intersecting Cold Pools: Convective Cloud Organization by Cold...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Intersecting Cold Pools: Convective Cloud Organization by Cold Pools over Tropical Ocean For original submission and image(s), see ARM Research Highlights http:www.arm.gov...

  8. ARM - Field Campaign - Deep Convective Clouds and Chemistry

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    govCampaignsDeep Convective Clouds and Chemistry Campaign Links DC3 Experiment Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Deep Convective Clouds and Chemistry 2012.05.01 - 2012.06.30 Lead Scientist : Christopher Cantrell Abstract The Deep Convective Clouds and Chemistry (DC3) sought to understand the influence of convection on the upper troposphere which will lead to better understanding of radiative forcing and chemical

  9. Making Sense of Convective Updrafts: Mass Flux and Microphysics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    model simulations contain a variety of complex dynamical structures that often do not map directly to the structural elements of convective parameterization. An example is...

  10. Summary of Convective Core Vertical Velocity Properties Using...

    Office of Scientific and Technical Information (OSTI)

    Title: Summary of Convective Core Vertical Velocity Properties Using ARM UHF Wind Profilers in Oklahoma Authors: Giangrande S. E. ; Collis, S. ; Straka, J. ; Protat, A. ; Williams, ...

  11. ARM - Field Campaign - ARM Support for the Plains Elevated Convection...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Convection at Night Experiment: Doppler Lidar Operations 2015.06.01, Turner, SGP Comments? ... Lead Scientist : David Turner For data sets, see below. Abstract The Plains Elevated ...

  12. ARM - Midlatitude Continental Convective Clouds Experiment (MC3E...

    Office of Scientific and Technical Information (OSTI)

    Vertical Air Motion (williams-vertair) Title: ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Vertical Air Motion (williams-vertair) ...

  13. ARM - Midlatitude Continental Convective Clouds Experiment (MC3E...

    Office of Scientific and Technical Information (OSTI)

    Parcivel Disdrometer (williams-disdro) Title: ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Parcivel Disdrometer (williams-disdro) ...

  14. Numerical Modeling Studies of The Dissolution-Diffusion-Convection...

    Office of Scientific and Technical Information (OSTI)

    Numerical Modeling Studies of The Dissolution-Diffusion-Convection ProcessDuring CO2 Storage in Saline Aquifers Citation Details In-Document Search Title: Numerical Modeling ...

  15. ARM - Midlatitude Continental Convective Clouds Experiment (MC3E...

    Office of Scientific and Technical Information (OSTI)

    Surface Meteorology (williams-surfmet) Title: ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Surface Meteorology (williams-surfmet) ...

  16. Arctic Stratus and Tropical Deep Convection. Integrating Measurements...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: Arctic Stratus and Tropical Deep Convection. Integrating Measurements and Simulations Citation Details In-Document Search Title: Arctic Stratus and Tropical Deep ...

  17. Interactions between cumulus convection and its environment as...

    Office of Scientific and Technical Information (OSTI)

    Interactions between cumulus convection and its environment as revealed by the MC3E sounding array Citation Details In-Document Search Title: Interactions between cumulus ...

  18. Interactions between cumulus convection and its environment as...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Interactions between cumulus convection and its environment as revealed by the MC3E sounding array Citation Details In-Document Search Title: Interactions between ...

  19. Optimal Disturbances in Three-Dimensional Natural Convection...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Optimal Disturbances in Three-Dimensional Natural Convection ... Buoyancy-driven systems are subject to several types of flow ... solvers 1 in combination with a power iteration 2. ...

  20. CAPE-OPEN compliant stochastic modeling and reduced-order model computation capability for APECS system

    SciTech Connect (OSTI)

    Diwekar, Urmila; Shastri, Yogendra (Vishwamitra Research Institute Clarendon Hills, IL); Subrmanyan, Karthik; Zitney, S.E.

    2007-11-04

    APECS (Advanced Process Engineering Co-Simulator) is an integrated software suite that combines the power of process simulation with high-fidelity, computational fluid dynamics (CFD) for improved design, analysis, and optimization of process engineering systems. The APECS system uses commercial process simulation (e.g., Aspen Plus) and CFD (e.g., FLUENT) software integrated with the process-industry standard CAPE-OPEN (CO) interfaces. This breakthrough capability allows engineers to better understand and optimize the fluid mechanics that drive overall power plant performance and efficiency. The focus of this paper is the CAPE-OPEN complaint stochastic modeling and reduced order model computational capability around the APECS system. The usefulness of capabilities is illustrated with coal fired, gasification based, FutureGen power plant simulation. These capabilities are used to generate efficient reduced order models and optimizing model complexities.

  1. Review of the physical oceanography of the Cape Hatteras, North Carolina Region. Volume 1. Literature synthesis

    SciTech Connect (OSTI)

    Adams, C.E.; Berger, T.J.; Boicourt, W.C.; Churchill, J.H.; Earle, M.D.

    1993-10-01

    The present study is part of a sequence of programs designed to provide the MMS with a basis for evaluating the potential environmental impacts of oil and gas production off of the Cape Hatteras region. The primary objective of this review is to summarize and critique the present state of knowledge of the physical oceanography of the complex region offshore of Cape Hatteras, North Carolina, within the context of understanding the regional circulation and its relation to the fate of any discharges resulting from offshore oil and gas activity. The two other related objectives are to produce an annotated bibliography of the pertinent literature, primarily from 1970 to the present, and to identify relevant oceanographic data sets which can provide a basis for an improved understanding of circulation patterns and physical oceanographic conditions in the study area.

  2. Benthic study of the continental slope off Cape Hatteras, North Carolina. Volume 2. Final report

    SciTech Connect (OSTI)

    Diaz, R.J.; Blake, J.A.; Lohse, D.P.

    1993-03-01

    A number of blocks off Cape Hatteras have been leased by Mobil Oil, which has requested permission to drill an exploratory well, at 820-m depth, in a block identified as Manteo 467. The proposed well location is 39 miles from the coast of North Carolina. The possibility of extracting gas from the continental slope off the coast of North Carolina, particularly at slope depths, has raised a number of environmental concerns that cannot be addressed from existing data. The present study was developed by the Minerals Management Service to better define the nature of the continental slope benthic communities off Cape Hatteras and to delineate their areal extent. Emphasis was placed on the area around the proposed drill site in the Manteo 467 lease block.

  3. Characterizing the convective velocity fields in massive stars

    SciTech Connect (OSTI)

    Chatzopoulos, Emmanouil; Graziani, Carlo; Couch, Sean M.

    2014-11-01

    We apply the mathematical formalism of vector spherical harmonics decomposition to convective stellar velocity fields from multidimensional hydrodynamics simulations and show that the resulting power spectra furnish a robust and stable statistical description of stellar convective turbulence. Analysis of the power spectra helps identify key physical parameters of the convective process such as the dominant scale of the turbulent motions that influence the structure of massive evolved pre-supernova stars. We introduce the numerical method that can be used to calculate vector spherical harmonics power spectra from two-dimensional (2D) and three-dimensional (3D) convective shell simulation data. Using this method we study the properties of oxygen shell burning and convection for a 15 M {sub ☉} star simulated by the hydrodynamics code FLASH in 2D and 3D. We discuss the importance of realistic initial conditions to achieving successful core-collapse supernova explosions in multidimensional simulations. We show that the calculated power spectra can be used to generate realizations of the velocity fields of presupernova convective shells. We find that the slope of the solenoidal mode power spectrum remains mostly constant throughout the evolution of convection in the oxygen shell in both 2D and 3D simulations. We also find that the characteristic radial scales of the convective elements are smaller in 3D than in 2D, while the angular scales are larger in 3D.

  4. Interaction of externally-driven acoustic waves with compressible convection

    SciTech Connect (OSTI)

    Jones, P. ); Merryfield, W. . Dept. of Physics and Astronomy); Toomre, J. )

    1992-01-01

    Two-dimensional numerical simulations are used to examine the interaction of acoustic waves with a compressible convecting fluid. Acoustic waves are forced at the lower boundary of the computational domain and propagate through a three-layer system undergoing vigorous penetrative convection. Energy exchange between the wave and the fluid is analyzed using a work integral formulation.

  5. Interaction of externally-driven acoustic waves with compressible convection

    SciTech Connect (OSTI)

    Jones, P.; Merryfield, W.; Toomre, J.

    1992-12-01

    Two-dimensional numerical simulations are used to examine the interaction of acoustic waves with a compressible convecting fluid. Acoustic waves are forced at the lower boundary of the computational domain and propagate through a three-layer system undergoing vigorous penetrative convection. Energy exchange between the wave and the fluid is analyzed using a work integral formulation.

  6. Plains Elevated Convection at Night (PECAN) Experiment Science Plan

    SciTech Connect (OSTI)

    Turner, D; Parsons, D; Geerts, B

    2015-03-01

    The Plains Elevated Convection at Night (PECAN) experiment is a large field campaign that is being supported by the National Science Foundation (NSF) with contributions from the National Oceanic and Atmospheric Administration (NOAA), the National Atmospheric and Space Administration (NASA), and the U.S. Department of Energy (DOE). The overarching goal of the PECAN experiment is to improve the understanding and simulation of the processes that initiate and maintain convection and convective precipitation at night over the central portion of the Great Plains region of the United States (Parsons et al. 2013). These goals are important because (1) a large fraction of the yearly precipitation in the Great Plains comes from nocturnal convection, (2) nocturnal convection in the Great Plains is most often decoupled from the ground and, thus, is forced by other phenomena aloft (e.g., propagating bores, frontal boundaries, low-level jets [LLJ], etc.), (3) there is a relative lack of understanding how these disturbances initiate and maintain nocturnal convection, and (4) this lack of understanding greatly hampers the ability of numerical weather and climate models to simulate nocturnal convection well. This leads to significant uncertainties in predicting the onset, location, frequency, and intensity of convective cloud systems and associated weather hazards over the Great Plains.

  7. ARM - Midlatitude Continental Convective Clouds Microwave Radiometer...

    Office of Scientific and Technical Information (OSTI)

    of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. ...

  8. Magnetogenesis through convection in barotropic fluids

    SciTech Connect (OSTI)

    Miller, E. Rogers, B.

    2015-04-15

    It is shown that an unmagnetized plasma with non-uniform bulk velocity can generate magnetic fields through consideration of the non-relativistic isentropic two-fluid equations, even when the initial conditions contain with no fields or currents, uniform densities and pressures, and a divergence-free bulk velocity. This effect does not depend on the baroclinicity of the plasma and is therefore relevant even in barotropic flows, where the Biermann battery is absent. It also does not rely on kinetic effects or shear discontinuities. Instead, our magnetogenesis effect arises from convection terms proportional to the electron mass in the generalized Ohm's law. The resulting magnetic fields are typically weak but may still serve as seed fields for dynamo mechanisms.

  9. DOE Zero Ready Home Case Study: John Hubert Associates, EXIT-0, North Cape May, NJ

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Hubert Associates EXIT-0 House North Cape May, NJ DOE ZERO ENERGY READY HOME(tm) The U.S. Department of Energy invites home builders across the country to meet the extraordinary levels of excellence and quality specified in DOE's Zero Energy Ready Home program (formerly known as Challenge Home). Every DOE Zero Energy Ready Home starts with ENERGY STAR Certified Homes Version 3.0 for an energy-efficient home built on a solid foundation of building science research. Advanced technologies are

  10. Benthic study of the continental slope off Cape Hatteras, North Carolina. Volume 3. Appendices

    SciTech Connect (OSTI)

    Diaz, R.J.; Blake, J.A.; Lohse, D.P.

    1993-03-01

    The Point is an area that supports a most productive pelagic fishery, including tuna, swordfish, marlin, and more. The objective of the study is to analyze video tapes from near the Point, in order to provide data on epibenthic, megafaunal invertebrates including species composition, relative abundances, and large scale (1 km) distribution. The Point is not a defined spot on a chart. Although fishermen do use the steep shelf break for location, they generally look for the west wall of the Gulf Stream. The Point and the oil lease site coincidentally occur where the Gulf Stream parts the continental slope, just north of the eastern-most tip of Cape Hatteras.

  11. Free convective condensation in a vertical enclosure

    SciTech Connect (OSTI)

    Fox, R.J.; Peterson, P.F.; Corradini, M.L.; Pernsteiner, A.P.

    1995-09-01

    Free convective condensation in a vertical enclosure was studied numerically and the results were compared with experiments. In both the numerical and experimental investigations, mist formation was observed to occur near the cooling wall, with significant droplet concentrations in the bulk. Large recirculation cells near the end of the condensing section were generated as the heavy noncondensing gas collecting near the cooling wall was accelerated downward. Near the top of the enclosure the recirculation cells became weaker and smaller than those below, ultimately disappearing near the top of the condenser. In the experiment the mist density was seen to be highest near the wall and at the bottom of the condensing section, whereas the numerical model predicted a much more uniform distribution. The model used to describe the formation of mist was based on a Modified Critical Saturation Model (MCSM), which allows mist to be generated once the vapor pressure exceeds a critical value. Equilibrium, nonequilibrium, and MCSM calculations were preformed, showing the experimental results to lie somewhere in between the equilibrium and nonequilibrium predictions of the numerical model. A single adjustable constant (indicating the degree to which equilibrium is achieved) is used in the model in order to match the experimental results.

  12. EVIDENCE FOR CONVECTION IN SUNSPOT PENUMBRAE

    SciTech Connect (OSTI)

    Bharti, L.; Solanki, S. K.; Hirzberger, J.

    2010-10-20

    We present an analysis of twisting motions in penumbral filaments in sunspots located at heliocentric angles from 30{sup 0} to 48{sup 0} using three time series of blue continuum images obtained by the Broadband Filter Imager (BFI) on board Hinode. The relations of the twisting motions to the filament brightness and the position within the filament and within the penumbra, respectively, are investigated. Only certain portions of the filaments show twisting motions. In a statistical sense, the part of the twisting portion of a filament located closest to the umbra is brightest and possesses the fastest twisting motion, with a mean twisting velocity of 2.1 km s{sup -1}. The middle and outer sections of the twisting portion of the filament (lying increasingly further from the umbra), which are less bright, have mean velocities of 1.7 km s{sup -1} and 1.35 km s{sup -1}, respectively. The observed reduction of brightness and twisting velocity toward the outer section of the filaments may be due to reducing upflow along the filament's long axis. No significant variation of twisting velocity as a function of viewing angles was found. The obtained correlation of brightness and velocity suggests that overturning convection causes the twisting motions observed in penumbral filament and may be the source of the energy needed to maintain the brightness of the filaments.

  13. ARM - Midlatitude Continental Convective Clouds Experiment (MC3E...

    Office of Scientific and Technical Information (OSTI)

    S-band Radar (williams-sband) Title: ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, S-band Radar (williams-sband) This data was ...

  14. ARM - Midlatitude Continental Convective Clouds Experiment (MC3E...

    Office of Scientific and Technical Information (OSTI)

    ...filer(williams-449prof) Title: ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, 449 MHz Profiler(williams-449prof) This data was ...

  15. NATURAL CONVECTION IN PASSIVE SOLAR BUILDINGS: EXPERIMENTS, ANALYSIS AND RESULTS

    SciTech Connect (OSTI)

    Gadgil, A.; Bauman, F.; Kammerud, R.

    1981-04-01

    Computer programs have been developed to numerically simulate natural convection in two- and three-dimensional room geometries. The programs have been validated using published data from the literature, results from a full-scale experiment performed at the Massachusetts Institute of Technology, and results from a small-scale experiment performed at LBL. One of the computer programs has been used to study the influence of natural convection on the thermal performance of a single zone in a direct-gain passive solar building. It is found that the convective heat transfer coefficients between the air and the enclosure surfaces can be substantially different from the values assumed in the standard building energy analysis methods, and can exhibit significant variations across a given surface. This study implies that the building heating loads calculated by standard building energy analysis methods may have substantial errors as a result of their use of common assumptions regarding the convection processes which occur in an enclosure.

  16. Simple Analysis of Flame Dynamics via Flexible Convected Disturbance...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Simple Analysis of Flame Dynamics via Flexible Convected Disturbance ... OSTI Identifier: 1160232 Report Number(s): A-NETL-PUB-020 Journal ID: ISSN 0748-4658 ...

  17. EIS-0470: U.S. Department of Energy Loan Guarantee for the Cape Wind Energy Project on the Outer Continental Shelf off Massachusetts, Nantucket Sound

    Broader source: Energy.gov [DOE]

    The DOE Loan Programs Office is proposing to offer a loan guarantee to Cape Wind Associates, LLC for the construction and start-up of the Cape Wind Energy Project in Nantucket Sound, offshore of Massachusetts. The proposed Cape Wind Energy Project would consist of up to 130, 3.6-MW turbine generators, in an area of roughly 25-square miles, and would include 12.5 miles of 115-kilovolt submarine transmission cable and an electric service platform. To inform DOE's decision regarding a loan guarantee, DOE adopted the Department of the Interior’s 2009 Final Cape Wind Energy Project EIS, in combination with two Cape Wind Environmental Assessments dated May 2010 and April 2011 (per 40 CFR 1506.4), as a DOE Final EIS (DOE/EIS-0470). The adequacy of the Department of the Interior final EIS adopted by DOE is the subject of a judicial action. This project is inactive.

  18. Vertical microphysical profiles of convective clouds as a tool for

    Office of Scientific and Technical Information (OSTI)

    obtaining aerosol cloud-mediated climate forcings (Technical Report) | SciTech Connect Vertical microphysical profiles of convective clouds as a tool for obtaining aerosol cloud-mediated climate forcings Citation Details In-Document Search Title: Vertical microphysical profiles of convective clouds as a tool for obtaining aerosol cloud-mediated climate forcings Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud

  19. Natural convection airflow and heat transport in buildings: experimental results

    SciTech Connect (OSTI)

    Balcomb, J.D.; Jones, G.F.

    1985-01-01

    Observations of natural convection airflow in passive solar buildings are described. Particular results are given for two buildings supplementing other data already published. A number of generalizations based on the monitoring of the 15 buildings are presented. It is concluded that energy can be reasonably well distributed throughout a building by natural convection provided suitable openings are present and that the direction of heat transport is either horizontally across or upward.

  20. Convection feedbacks in a super-parameterization GCM

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Convection feedbacks in a super-parameterization GCM Luo, Zhengzhao (Johnny) Colorado State University Stephens, Graeme Colorado State University Category: Modeling Both the Colorado State University (CSU) and Goddard super-parameterization GCM (SP-GCM) simulate a super-active Asian summer monsoon with unrealistically enhanced levels of precipitation. The underlying physical mechanism for this monsoon bias in the CSU SP-GCM is shown to involve enhanced convection-wind-evaporation feedbacks. The

  1. Natural convection heat transfer within horizontal spent nuclear fuel assemblies

    SciTech Connect (OSTI)

    Canaan, R.E.

    1995-12-01

    Natural convection heat transfer is experimentally investigated in an enclosed horizontal rod bundle, which characterizes a spent nuclear fuel assembly during dry storage and/or transport conditions. The basic test section consists of a square array of sixty-four stainless steel tubular heaters enclosed within a water-cooled rectangular copper heat exchanger. The heaters are supplied with a uniform power generation per unit length while the surrounding enclosure is maintained at a uniform temperature. The test section resides within a vacuum/pressure chamber in order to subject the assembly to a range of pressure statepoints and various backfill gases. The objective of this experimental study is to obtain convection correlations which can be used in order to easily incorporate convective effects into analytical models of horizontal spent fuel systems, and also to investigate the physical nature of natural convection in enclosed horizontal rod bundles in general. The resulting data consist of: (1) measured temperatures within the assembly as a function of power, pressure, and backfill gas; (2) the relative radiative contribution for the range of observed temperatures; (3) correlations of convective Nusselt number and Rayleigh number for the rod bundle as a whole; and (4) correlations of convective Nusselt number as a function of Rayleigh number for individual rods within the array.

  2. Final Technical Report for "Radiative Heating Associated with Tropical Convective Cloud Systems: Its Importance at Meso and Global Scales"

    SciTech Connect (OSTI)

    Schumacher, Courtney

    2012-12-13

    Heating associated with tropical cloud systems drive the global circulation. The overall research objectives of this project were to i) further quantify and understand the importance of heating in tropical convective cloud systems with innovative observational techniques, and ii) use global models to determine the large-scale circulation response to variability in tropical heating profiles, including anvil and cirrus cloud radiative forcing. The innovative observational techniques used a diversity of radar systems to create a climatology of vertical velocities associated with the full tropical convective cloud spectrum along with a dissection of the of the total heating profile of tropical cloud systems into separate components (i.e., the latent, radiative, and eddy sensible heating). These properties were used to validate storm-scale and global climate models (GCMs) and were further used to force two different types of GCMs (one with and one without interactive physics). While radiative heating was shown to account for about 20% of the total heating and did not have a strong direct response on the global circulation, the indirect response was important via its impact on convection, esp. in how radiative heating impacts the tilt of heating associated with the Madden-Julian Oscillation (MJO), a phenomenon that accounts for most tropical intraseasonal variability. This work shows strong promise in determining the sensitivity of climate models and climate processes to heating variations associated with cloud systems.

  3. Review of the physical oceanography of the Cape Hatteras, North Carolina Region. Volume 1. Literature synthesis. Appendix A. Annotated bibliography

    SciTech Connect (OSTI)

    Adams, C.E.; Berger, T.J.; Boicourt, W.C.; Churchill, J.H.; Earle, M.D.

    1993-10-01

    The report, second in a three set series, is an annotated bibliography of the pertinent literature, primarily from 1970 to the present. The literature discusses the physical oceanography of the complex region offshore of Cape Hatteras, North Carolina as it relates to the ocean circulation and fate of any discharges resulting from offshore oil and gas activity.

  4. Temperature, humidity and air flow in the emplacement drifts using convection and dispersion transport models

    SciTech Connect (OSTI)

    Danko, G.; Birkholzer, J.T.; Bahrami, D.; Halecky, N.

    2009-10-01

    A coupled thermal-hydrologic-airflow model is developed, solving for the transport processes within a waste emplacement drift and the surrounding rockmass together at the proposed nuclear waste repository at Yucca Mountain. Natural, convective air flow as well as heat and mass transport in a representative emplacement drift during post-closure are explicitly simulated, using the MULTIFLUX model. The conjugate, thermal-hydrologic transport processes in the rockmass are solved with the TOUGH2 porous-media simulator in a coupled way to the in-drift processes. The new simulation results show that large-eddy turbulent flow, as opposed to small-eddy flow, dominate the drift air space for at least 5000 years following waste emplacement. The size of the largest, longitudinal eddy is equal to half of the drift length, providing a strong axial heat and moisture transport mechanism from the hot to the cold drift sections. The in-drift results are compared to those from simplified models using a surrogate, dispersive model with an equivalent dispersion coefficient for heat and moisture transport. Results from the explicit, convective velocity simulation model provide higher axial heat and moisture fluxes than those estimated from the previously published, simpler, equivalent-dispersion models, in addition to showing differences in temperature, humidity and condensation rate distributions along the drift length. A new dispersive model is also formulated, giving a time- and location-variable function that runs generally about ten times higher in value than the highest dispersion coefficient currently used in the Yucca Mountain Project as an estimate for the equivalent dispersion coefficient in the emplacement drift. The new dispersion coefficient variation, back-calculated from the convective model, can adequately describe the heat and mass transport processes in the emplacement drift example.

  5. Package Equivalent Reactor Networks as Reduced Order Models for Use with CAPE-OPEN Compliant Simulation

    SciTech Connect (OSTI)

    Meeks, E.; Chou, C. -P.; Garratt, T.

    2013-03-31

    high-fidelity kinetics simulation, while maintaining the spatial information derived from the geometrically faithful CFD model. The reduced-order models are generated in such a way that they can be easily imported into a process flowsheet simulator, using the CAPE-OPEN architecture for unit operations. The ENERGICO/CHEMKIN-PRO software produces an ERN-definition file that is read by a dynamically linked library (DLL) that can be easily linked to any CAPE-OPEN compliant software. The plug-in unitoperation module has been successfully demonstrated for complex ERNs of coal gasifiers, using both Aspen Plus and COFE process flowsheet simulators through this published CAPE-OPEN interface.

  6. Interactions between a tropical mixed boundary layer and cumulus convection in a radiative-convective model

    SciTech Connect (OSTI)

    Dean, C.L.

    1993-05-01

    This report details a radiative-convective model, combining previously developed cumulus, stable cloud and radiation parameterizations with a boundary layer scheme, which was developed in the current study. The cloud model was modified to incorporate the effects of both small and large clouds. The boundary layer model was adapted from a mixed layer model was only slightly modified to couple it with the more sophisticated cloud model. The model was tested for a variety of imposed divergence profiles, which simulate the regions of the tropical ocean from approximately the intertropical Convergence Zone (ITCZ) to the subtropical high region. The sounding used to initialize the model for most of the runs is from the trade wind region of ATEX. For each experiment, the model was run with a timestep of 300 seconds for a period of 7 days.

  7. A simulation of convective dynamo in the solar convective envelope: Maintenance of the solar-like differential rotation and emerging flux

    SciTech Connect (OSTI)

    Fan, Yuhong; Fang, Fang

    2014-07-01

    We report the results of a magnetohydrodynamic (MHD) simulation of a convective dynamo in a model solar convective envelope driven by the solar radiative diffusive heat flux. The convective dynamo produces a large-scale mean magnetic field that exhibits irregular cyclic behavior with oscillation time scales ranging from about 5 to 15 yr and undergoes irregular polarity reversals. The mean axisymmetric toroidal magnetic field is of opposite signs in the two hemispheres and is concentrated at the bottom of the convection zone. The presence of the magnetic fields is found to play an important role in the self-consistent maintenance of a solar-like differential rotation in the convective dynamo model. Without the magnetic fields, the convective flows drive a differential rotation with a faster rotating polar region. In the midst of magneto-convection, we found the emergence of strong super-equipartition flux bundles at the surface, exhibiting properties that are similar to emerging solar active regions.

  8. Turbulent natural and mixed convection along a vertical plate

    SciTech Connect (OSTI)

    Abu-Mulaweh, H.I.; Armaly, B.F.; Chen, T.S.; Zhao, J.Z.

    1997-07-01

    Measurements of turbulent boundary-layer air flow in natural and mixed convection adjacent to an isothermal vertical flat plate are reported. Laser-Doppler velocimeter and cold wire anemometer were used, respectively, to measure simultaneously the mean turbulent velocity and temperature distributions were measured for a temperature difference, {Delta}T, of 30 C between the heated wall and the free stream air at a fixed location x = 3 m (with a corresponding Grashof number Gr{sub x} = 8.55 x 10{sup 10}), and for a range of free stream velocities 0 m/s {le} U{sub {infinity} } {le} 0.41 m/s. The effect of small free stream velocity on the turbulent natural convection is examined. These results reveal that the introduction of small free stream velocity on turbulent natural convection flow suppresses turbulence and decreases the heat transfer rate from the heated wall.

  9. ARM - Midlatitude Continental Convective Clouds (comstock-hvps)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  10. ARM - Midlatitude Continental Convective Clouds (comstock-hvps)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    2012-01-06

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  11. ARM - Field Campaign - CROC - Convective Radio Occultations Campaign

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    govCampaignsCROC - Convective Radio Occultations Campaign ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : CROC - Convective Radio Occultations Campaign 2012.02.01 - 2014.12.31 Lead Scientist : Riccardo Biondi For data sets, see below. Abstract This campaign acquired in situ measurements (cloud base, cloud top, profiles of backscatter, temperature and water vapor) co-located with the Global Positioning

  12. ARM - Field Campaign - Midlatitude Continental Convective Clouds Experiment

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    (MC3E): Multi-Frequency Profilers Experiment (MC3E): Multi-Frequency Profilers ARM Data Discovery Browse Data Related Campaigns Midlatitude Continental Convective Clouds Experiment (MC3E) 2011.04.22, Jensen, SGP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers 2011.04.22 - 2011.06.06 Lead Scientist : Christopher Williams For data sets, see below.

  13. A meshless method for modeling convective heat transfer

    SciTech Connect (OSTI)

    Carrington, David B

    2010-01-01

    A meshless method is used in a projection-based approach to solve the primitive equations for fluid flow with heat transfer. The method is easy to implement in a MATLAB format. Radial basis functions are used to solve two benchmark test cases: natural convection in a square enclosure and flow with forced convection over a backward facing step. The results are compared with two popular and widely used commercial codes: COMSOL, a finite element model, and FLUENT, a finite volume-based model.

  14. Calibration of a Convective Parameterization Scheme in the WRF Model and its Impact on the Simulation of East Asian Summer Monsoon Precipitation

    SciTech Connect (OSTI)

    Yang, Ben; Zhang, Yaocun; Qian, Yun; Huang, Anning; Yan, Huiping

    2015-03-26

    Reasonably modeling the magnitude, south-north gradient and seasonal propagation of precipitation associated with the East Asian Summer Monsoon (EASM) is a challenging task in the climate community. In this study we calibrate five key parameters in the Kain-Fritsch convection scheme in the WRF model using an efficient importance-sampling algorithm to improve the EASM simulation. We also examine the impacts of the improved EASM precipitation on other physical process. Our results suggest similar model sensitivity and values of optimized parameters across years with different EASM intensities. By applying the optimal parameters, the simulated precipitation and surface energy features are generally improved. The parameters related to downdraft, entrainment coefficients and CAPE consumption time (CCT) can most sensitively affect the precipitation and atmospheric features. Larger downdraft coefficient or CCT decrease the heavy rainfall frequency, while larger entrainment coefficient delays the convection development but build up more potential for heavy rainfall events, causing a possible northward shift of rainfall distribution. The CCT is the most sensitive parameter over wet region and the downdraft parameter plays more important roles over drier northern region. Long-term simulations confirm that by using the optimized parameters the precipitation distributions are better simulated in both weak and strong EASM years. Due to more reasonable simulated precipitation condensational heating, the monsoon circulations are also improved. By using the optimized parameters the biases in the retreating (beginning) of Mei-yu (northern China rainfall) simulated by the standard WRF model are evidently reduced and the seasonal and sub-seasonal variations of the monsoon precipitation are remarkably improved.

  15. Calibration of a convective parameterization scheme in the WRF model and its impact on the simulation of East Asian summer monsoon precipitation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yang, Ben; Zhang, Yaocun; Qian, Yun; Huang, Anning; Yan, Huiping

    2014-03-26

    Reasonably modeling the magnitude, south-north gradient and seasonal propagation of precipitation associated with the East Asian Summer Monsoon (EASM) is a challenging task in the climate community. In this study we calibrate five key parameters in the Kain-Fritsch convection scheme in the WRF model using an efficient importance-sampling algorithm to improve the EASM simulation. We also examine the impacts of the improved EASM precipitation on other physical process. Our results suggest similar model sensitivity and values of optimized parameters across years with different EASM intensities. By applying the optimal parameters, the simulated precipitation and surface energy features are generally improved.more » The parameters related to downdraft, entrainment coefficients and CAPE consumption time (CCT) can most sensitively affect the precipitation and atmospheric features. Larger downdraft coefficient or CCT decrease the heavy rainfall frequency, while larger entrainment coefficient delays the convection development but build up more potential for heavy rainfall events, causing a possible northward shift of rainfall distribution. The CCT is the most sensitive parameter over wet region and the downdraft parameter plays more important roles over drier northern region. Long-term simulations confirm that by using the optimized parameters the precipitation distributions are better simulated in both weak and strong EASM years. Due to more reasonable simulated precipitation condensational heating, the monsoon circulations are also improved. Lastly, by using the optimized parameters the biases in the retreating (beginning) of Mei-yu (northern China rainfall) simulated by the standard WRF model are evidently reduced and the seasonal and sub-seasonal variations of the monsoon precipitation are remarkably improved.« less

  16. 2-D and 3-D Models of Convective Turbulence and Oscillations...

    Office of Scientific and Technical Information (OSTI)

    2-D and 3-D Models of Convective Turbulence and Oscillations in Intermediate-Mass Main-Sequence Stars Citation Details In-Document Search Title: 2-D and 3-D Models of Convective ...

  17. Convection venting lensed reflector-type compact fluorescent lamp system

    DOE Patents [OSTI]

    Pelton, Bruce A.; Siminovitch, Michael

    1997-01-01

    Disclosed herein is a fluorescent lamp housing assembly capable of providing convection cooling to the lamp and the ballast. The lens of the present invention includes two distinct portions, a central portion and an apertured portion. The housing assembly further includes apertures so that air mass is able to freely move up through the assembly and out ventilation apertures.

  18. ON THE VIGOR OF MANTLE CONVECTION IN SUPER-EARTHS

    SciTech Connect (OSTI)

    Miyagoshi, Takehiro; Tachinami, Chihiro; Kameyama, Masanori; Ogawa, Masaki E-mail: ctchnm.geo@gmail.com E-mail: cmaogawa@mail.ecc.u-tokyo.ac.jp

    2014-01-01

    Numerical models are presented to clarify how adiabatic compression affects thermal convection in the mantle of super-Earths tentimes the Earth's mass. The viscosity strongly depends on temperature, and the Rayleigh number is much higher than that of the Earth's mantle. The strong effect of adiabatic compression reduces the activity of mantle convection; hot plumes ascending from the bottom of the mantle lose their thermal buoyancy in the middle of the mantle owing to adiabatic decompression, and do not reach the surface. A thick lithosphere, as thick as 0.1times the depth of the mantle, develops along the surface boundary, and the efficiency of convective heat transport measured by the Nusselt number is reduced by a factor of about four compared with the Nusselt number for thermal convection of incompressible fluid. The strong effect of adiabatic decompression is likely to inhibit hot spot volcanism on the surface and is also likely to affect the thermal history of the mantle, and hence, the generation of magnetic field in super-Earths.

  19. Convection venting lensed reflector-type compact fluorescent lamp system

    DOE Patents [OSTI]

    Pelton, B.A.; Siminovitch, M.

    1997-07-29

    Disclosed herein is a fluorescent lamp housing assembly capable of providing convection cooling to the lamp and the ballast. The lens of the present invention includes two distinct portions, a central portion and an apertured portion. The housing assembly further includes apertures so that air mass is able to freely move up through the assembly and out ventilation apertures. 12 figs.

  20. Two-phase convective CO2 dissolution in saline aquifers

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Martinez, Mario J.; Hesse, Marc A.

    2016-01-01

    Geologic carbon storage in deep saline aquifers is a promising technology for reducing anthropogenic emissions into the atmosphere. Dissolution of injected CO2 into resident brines is one of the primary trapping mechanisms generally considered necessary to provide long-term storage security. Given that diffusion of CO2 in brine is woefully slow, convective dissolution, driven by a small increase in brine density with CO2 saturation, is considered to be the primary mechanism of dissolution trapping. Previous studies of convective dissolution have typically only considered the convective process in the single-phase region below the capillary transition zone and have either ignored the overlyingmore » two-phase region where dissolution actually takes place or replaced it with a virtual region with reduced or enhanced constant permeability. Our objective is to improve estimates of the long-term dissolution flux of CO2 into brine by including the capillary transition zone in two-phase model simulations. In the fully two-phase model, there is a capillary transition zone above the brine-saturated region over which the brine saturation decreases with increasing elevation. Our two-phase simulations show that the dissolution flux obtained by assuming a brine-saturated, single-phase porous region with a closed upper boundary is recovered in the limit of vanishing entry pressure and capillary transition zone. For typical finite entry pressures and capillary transition zone, however, convection currents penetrate into the two-phase region. As a result, this removes the mass transfer limitation of the diffusive boundary layer and enhances the convective dissolution flux of CO2 more than 3 times above the rate assuming single-phase conditions.« less

  1. Analysis of Cloud-resolving Simulations of a Tropical Mesoscale Convective System Observed during TWP-ICE: Vertical Fluxes and Draft Properties in Convective and Stratiform Regions

    SciTech Connect (OSTI)

    Mrowiec, Agnieszka A.; Rio, Catherine; Fridlind, Ann; Ackerman, Andrew; Del Genio, Anthony D.; Pauluis, Olivier; Varble, Adam; Fan, Jiwen

    2012-10-02

    We analyze three cloud-resolving model simulations of a strong convective event observed during the TWP-ICE campaign, differing in dynamical core, microphysical scheme or both. Based on simulated and observed radar reflectivity, simulations roughly reproduce observed convective and stratiform precipitating areas. To identify the characteristics of convective and stratiform drafts that are difficult to observe but relevant to climate model parameterization, independent vertical wind speed thresholds are calculated to capture 90% of total convective and stratiform updraft and downdraft mass fluxes. Convective updrafts are fairly consistent across simulations (likely owing to fixed large-scale forcings and surface conditions), except that hydrometeor loadings differ substantially. Convective downdraft and stratiform updraft and downdraft mass fluxes vary notably below the melting level, but share similar vertically uniform draft velocities despite differing hydrometeor loadings. All identified convective and stratiform downdrafts contain precipitation below ~10 km and nearly all updrafts are cloudy above the melting level. Cold pool properties diverge substantially in a manner that is consistent with convective downdraft mass flux differences below the melting level. Despite differences in hydrometeor loadings and cold pool properties, convective updraft and downdraft mass fluxes are linearly correlated with convective area, the ratio of ice in downdrafts to that in updrafts is ~0.5 independent of species, and the ratio of downdraft to updraft mass flux is ~0.5-0.6, which may represent a minimum evaporation efficiency under moist conditions. Hydrometeor loading in stratiform regions is found to be a fraction of hydrometeor loading in convective regions that ranges from ~10% (graupel) to ~90% (cloud ice). These findings may lead to improved convection parameterizations.

  2. Use of CAPE-OPEN Standard in US-UK Collaboration on Virtual Plant Simulation

    SciTech Connect (OSTI)

    Zitney, S.E.

    2007-11-01

    Under the auspices of a US-UK Memorandum of Understanding and Implementing Agreement for fossil energy R&D (http://us-uk.fossil.energy.gov/), the US Department of Energy’s (DOE) National Energy Technology Laboratory (NETL) and the UK Department of Trade and Industry (DTI) have recently completed a three-year collaboration on virtual plant modeling and simulation technology for advanced fossil-energy power generation systems. The R&D collaboration was aimed at taking full advantage of the synergies between NETL’s ongoing Advanced Process Engineering Co-Simulator (APECS) project and the UK’s three-year Virtual Plant Demonstration Model (VPDM) project. The key objective of this collaboration has been the development of compatible, open standards-based US and UK technology for process/equipment co-simulation. To achieve plug-and-play model interoperability, the collaboration leveraged the process-industry CAPE-OPEN (CO) software standard which is managed and disseminated by the CO Laboratories Network (www.colan.org).

  3. CAPE-OPEN Integration for Advanced Process Engineering Co-Simulation

    SciTech Connect (OSTI)

    Zitney, S.E.

    2006-11-01

    This paper highlights the use of the CAPE-OPEN (CO) standard interfaces in the Advanced Process Engineering Co-Simulator (APECS) developed at the National Energy Technology Laboratory (NETL). The APECS system uses the CO unit operation, thermodynamic, and reaction interfaces to provide its plug-and-play co-simulation capabilities, including the integration of process simulation with computational fluid dynamics (CFD) simulation. APECS also relies heavily on the use of a CO COM/CORBA bridge for running process/CFD co-simulations on multiple operating systems. For process optimization in the face of multiple and some time conflicting objectives, APECS offers stochastic modeling and multi-objective optimization capabilities developed to comply with the CO software standard. At NETL, system analysts are applying APECS to a wide variety of advanced power generation systems, ranging from small fuel cell systems to commercial-scale power plants including the coal-fired, gasification-based FutureGen power and hydrogen production plant.

  4. Geology and ground shaking: The April 25--26, 1992 Cape Mendocino earthquake sequence

    SciTech Connect (OSTI)

    Moley, K.; Dengler, L. . Dept. of Geology)

    1993-04-01

    The authors present a simplified geologic map of Humboldt and Del Norte Counties, California and compare it to Modified Mercalli Intensities (MMI) produced by the April 25, 1992 M[sub S] = 7.1, and April 26 Ms = 6.6, and Ms = 6.7 Cape Mendocino earthquakes. The generalized geology was compiled from California Division of Mines and Geology Regional Geology Maps, and area geologic mapping by the USGS and Humboldt State University. Six rock/sediment groups are distinguished by considering lithology, consolidation, compaction, bedding orientation and degree of shearing: (1) landslides and glacial deposits; (2) bay muds and fill, alluvium, lake deposits and beach sand; (3) quaternary marine and non-marine deposits; (4) unstable bedrock; (5) moderately stable bedrock; (6) intrusions. Intensity values for the Saturday earthquake were calculated from over 2,000 surveys to individuals and businesses in the northcoast area by an algorithm based on a weighted sum of survey responses. Numerical data was compiled for over 100 locations in the region. The intensity VIII and greater zone encompassed an area of about 500 km[sup 2] including the communities of Petrolia, Ferndale and Rio Dell. Ground motion generally decays with distance in a roughly radial pattern. A different approach was taken to estimate the pattern of shaking in the two Sunday earthquakes. These earthquakes occurred when most respondents were sleeping and their perception of ground motion was likely to be affected.

  5. Midlatitude Continental Convective Clouds Experiment (MC3E)

    SciTech Connect (OSTI)

    Jensen, MP; Petersen, WA; Del Genio, AD; Giangrande, SE; Heymsfield, A; Heymsfield, G; Hou, AY; Kollias, P; Orr, B; Rutledge, SA; Schwaller, MR; Zipser, E

    2010-04-10

    The Midlatitude Continental Convective Clouds Experiment (MC3E) will take place in central Oklahoma during the AprilMay 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility and the National Aeronautics and Space Administrations (NASA) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The field campaign leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors, and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that have never before been available.

  6. Numerical study of thermoacoustic convection in a cavity

    SciTech Connect (OSTI)

    Fusegi, Toru; Farouk, B.; Oran, E.S.

    1995-12-31

    Thermoacoustic convection in a two-dimensional cavity is numerically studied. Part of a compressible fluid (Helium) near the center line of the cavity is suddenly energized to generate pressure waves. Numerical solutions are secured by employing a highly accurate explicit method termed LCPFCT algorithm for the convection terms of the full Navier-Stokes equations. Thermoacoustic waves, which decay in large time due to the viscosity of fluid, are of the oscillatory nature. Much higher heat transfer rate can be achieved in an initial stage of transient processes, compared to that due to conduction. When a partial length of the cavity center line is heated, resulting thermoacoustic waves exhibit remarkable two-dimensional patterns.

  7. FULLY CONVECTIVE MAGNETOROTATIONAL TURBULENCE IN STRATIFIED SHEARING BOXES

    SciTech Connect (OSTI)

    Bodo, G.; Rossi, P.; Cattaneo, F.; Mignone, A.

    2013-07-10

    We present a numerical study of turbulence and dynamo action in stratified shearing boxes with zero magnetic flux. We assume that the fluid obeys the perfect gas law and has finite (constant) thermal diffusivity. We choose radiative boundary conditions at the vertical boundaries in which the heat flux is proportional to the fourth power of the temperature. We compare the results with the corresponding cases in which fixed temperature boundary conditions are applied. The most notable result is that the formation of a fully convective state in which the density is nearly constant as a function of height and the heat is transported to the upper and lower boundaries by overturning motions is robust and persists even in cases with radiative boundary conditions. Interestingly, in the convective regime, although the diffusive transport is negligible, the mean stratification does not relax to an adiabatic state.

  8. Laminar mixed convection in a horizontal eccentric annulus

    SciTech Connect (OSTI)

    Choudhury, D. ); Karki, K. )

    1992-01-01

    Laminar fluid flow and heat transfer phenomena in cylindrical annuli are encountered in various applications. The purpose of this paper is to present a numerical study of laminar mixed convection in horizontal eccentric annuli. Axial flow and heat transfer in a horizontal cylindrical annulus can be influenced by eccentricity of the inner cylinder and the presence of buoyancy forces. A numerical study is presented for the combined forced and free convection for the fully developed flow and heat transfer to eccentric annuli of different eccentricities and radius ratios. The flow field is characterized by large cross-stream secondary currents and significant flow distortion. The Nusselt number increases significantly with the Rayleigh number; the corresponding increase in the friction factor is relatively small. The eccentricity introduces additional nonuniformity of the flow and temperature fields.

  9. Influence of geometry on natural convection in buildings

    SciTech Connect (OSTI)

    White, M.D.; Winn, C.B.; Jones, G.F.; Balcomb, J.D.

    1985-01-01

    Strong free convection airflows occur within passive solar buildings resulting from elevated temperatures of surfaces irradiated by solar energy compared with the cooler surfaces not receiving radiation. The geometry of a building has a large influence on the directions and magnitudes of natural airflows, and thus heat transfer between zones. This investigation has utilized a variety of reduced-scale building configurations to study the effects of geometry on natural convection heat transfer. Similarity between the reduced-scale model and a full-scale passive solar building is achieved by having similar geometries and by replacing air with Freon-12 gas as the model's working fluid. Filling the model with Freon-12 gas results in similarity in Prandtl numbers and Rayleigh numbers based on temperature differences in the range from 10/sup 9/ to 10/sup 11/. Results from four geometries are described with an emphasis placed on the effects of heat loss on zone temperature stratification shifts.

  10. Natural convection burnout heat flux limit for control rods

    SciTech Connect (OSTI)

    Britt, T.E.

    1986-04-14

    Technical Standard 105-3.05, Safety Circuits, does not require the Septifoil Supply Header Pressure Very Low safety circuit for current charges. This document develops a new requirement for this circuit based on the burnout heat flux of a control rod under natural convective cooling. Specifically, the Septifoil Supply Header Pressure Very Low safety circuit will be required whenever the calculated control rod operating heat flux exceeds 155,000 pcu/ft{sup 2}-hr.

  11. ARM - Midlatitude Continental Convective Clouds Experiment (MC3E)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Related Links MC3E Home News News & Press MC3E Backgrounder (PDF, 1.61MB) SGP Images ARM flickr site Field Blog ARM Data Discovery Browse Data Deployment Operations Measurements Science Plan (PDF, 3.85 MB) Featured Data Plots SGP Data Plots (all) Experiment Planning Steering Committee Science Questions MC3E Proposal Abstract and Related Campaigns Meetings Cloud Life Cycle Working Group Contacts Michael Jensen, Lead Scientist Midlatitude Continental Convective Clouds Experiment (MC3E) Thanks

  12. Properties of tropical convection observed by ARM millimeter-radars

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Properties of tropical convection observed by ARM millimeter-radars Haynes, John Colorado State University Stephens, Graeme Colorado State University Category: Cloud Properties The results of an analysis of tropical cloud systems observed from a variety of vertically pointing radar systems are described. In particular, observations taken during five years of operation of the ARM millimeter wavelength radar system (MMCR) at Manus Island in the Tropical West Pacific region are characterized into

  13. AERIAL MEASUREMENTS OF CONVECTION CELL ELEMENTS IN HEATED LAKES

    SciTech Connect (OSTI)

    Villa-Aleman, E; Saleem Salaymeh, S; Timothy Brown, T; Alfred Garrett, A; Malcolm Pendergast, M; Linda Nichols, L

    2007-12-19

    Power plant-heated lakes are characterized by a temperature gradient in the thermal plume originating at the discharge of the power plant and terminating at the water intake. The maximum water temperature discharged by the power plant into the lake depends on the power generated at the facility and environmental regulations on the temperature of the lake. Besides the observed thermal plume, cloud-like thermal cells (convection cell elements) are also observed on the water surface. The size, shape and temperature of the convection cell elements depends on several parameters such as the lake water temperature, wind speed, surfactants and the depth of the thermocline. The Savannah River National Laboratory (SRNL) and Clemson University are collaborating to determine the applicability of laboratory empirical correlations between surface heat flux and thermal convection intensity. Laboratory experiments at Clemson University have demonstrated a simple relationship between the surface heat flux and the standard deviation of temperature fluctuations. Similar results were observed in the aerial thermal imagery SRNL collected at different locations along the thermal plume and at different elevations. SRNL will present evidence that the results at Clemson University are applicable to cooling lakes.

  14. Sensitivity of summer ensembles of fledgling superparameterized U.S. mesoscale convective systems to cloud resolving model microphysics and grid configuration

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Elliott, Elizabeth J.; Yu, Sungduk; Kooperman, Gabriel J.; Morrison, Hugh; Wang, Minghuai; Pritchard, Michael S.

    2016-05-01

    The sensitivities of simulated mesoscale convective systems (MCSs) in the central U.S. to microphysics and grid configuration are evaluated here in a global climate model (GCM) that also permits global-scale feedbacks and variability. Since conventional GCMs do not simulate MCSs, studying their sensitivities in a global framework useful for climate change simulations has not previously been possible. To date, MCS sensitivity experiments have relied on controlled cloud resolving model (CRM) studies with limited domains, which avoid internal variability and neglect feedbacks between local convection and larger-scale dynamics. However, recent work with superparameterized (SP) GCMs has shown that eastward propagating MCS-likemore » events are captured when embedded CRMs replace convective parameterizations. This study uses a SP version of the Community Atmosphere Model version 5 (SP-CAM5) to evaluate MCS sensitivities, applying an objective empirical orthogonal function algorithm to identify MCS-like events, and harmonizing composite storms to account for seasonal and spatial heterogeneity. A five-summer control simulation is used to assess the magnitude of internal and interannual variability relative to 10 sensitivity experiments with varied CRM parameters, including ice fall speed, one-moment and two-moment microphysics, and grid spacing. MCS sensitivities were found to be subtle with respect to internal variability, and indicate that ensembles of over 100 storms may be necessary to detect robust differences in SP-GCMs. Furthermore, these results emphasize that the properties of MCSs can vary widely across individual events, and improving their representation in global simulations with significant internal variability may require comparison to long (multidecadal) time series of observed events rather than single season field campaigns.« less

  15. Seasonal Variability in Clouds and Radiation at the Manus ARM Site

    SciTech Connect (OSTI)

    Mather, Jim H.

    2005-07-01

    The Atmospheric Radiation Measurement (ARM) program operates three climate observation stations in the tropical western Pacific region. Two of these sites, located on Manus island in Papua New Guinea and on the island republic of Nauru, have been operating for over five years. This data set provides an opportunity to examine variability in tropical cloudiness on a wide range of time scales. The focus of this study is on the annual cycle. The most obvious manifestation of the annual cycle in this region is the oscillation of monsoon convection between Asia and Australia. The impact of the annual cycle on Manus and Nauru is more subtle; however, analysis of radiation and cloud observations from the Manus and Nauru ARM sites reveals links to the annual monsoon cycle. One such link relates to the proximity of Manus to the Maritime Continent, the collection of islands separating the Pacific and Indian oceans. Convection over the large islands in the maritime continent exhibits a distinct annual cycle. Outflow from large-island convection is shown to modulate the cirrus population over Manus. During neutral or cool ENSO periods, convection over Nauru is relatively suppressed. During such periods, Nauru is shown to exhibit an annual cycle in local convective activity. During the inactive season, cirrus are often found near the tropopause over Nauru. These clouds are not formed directly by the outflow from convection. The seasonality and source of these clouds is also examined. Identifying the source of cirrus observed at Manus and Nauru is important because of the potential dependence of cirrus properties on the source of convection.

  16. SOUND-SPEED INVERSION OF THE SUN USING A NONLOCAL STATISTICAL CONVECTION THEORY

    SciTech Connect (OSTI)

    Zhang Chunguang; Deng Licai; Xiong Darun; Christensen-Dalsgaard, Jorgen

    2012-11-01

    Helioseismic inversions reveal a major discrepancy in sound speed between the Sun and the standard solar model just below the base of the solar convection zone. We demonstrate that this discrepancy is caused by the inherent shortcomings of the local mixing-length theory adopted in the standard solar model. Using a self-consistent nonlocal convection theory, we construct an envelope model of the Sun for sound-speed inversion. Our solar model has a very smooth transition from the convective envelope to the radiative interior, and the convective energy flux changes sign crossing the boundaries of the convection zone. It shows evident improvement over the standard solar model, with a significant reduction in the discrepancy in sound speed between the Sun and local convection models.

  17. Comparisons Of Two- And Three-Dimensional Convection In Type I X-Ray Bursts

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zingale, M.; Malone, C. M.; Nonaka, A.; Almgren, A. S.; Bell, J. B.

    2015-07-01

    We perform the first detailed three-dimensional simulation of low Mach number convection preceding runaway thermonuclear ignition in a mixed H/He X-ray burst. Our simulations include a moderate-sized, approximate network that captures hydrogen and helium burning up through rp-process breakout. We look at the difference between two- and three-dimensional convective fields, including the details of the turbulent convection.

  18. ARM - Midlatitude Continental Convective Clouds - Ultra High Sensitivity Aerosol Spectrometer(tomlinson-uhsas)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Tomlinson, Jason; Jensen, Mike

    2012-02-28

    Ultra High Sensitivity Aerosol Spectrometer (UHSASA) A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment. These files contain brightness temperatures observed at Purcell during MC3E. The measurements were made with a 5 channel (22.235, 23.035, 23.835, 26.235, 30.000GHz) microwave radiometer at one minute intervals. The results have been separated into daily files and the day of observations is indicated in the file name. All observations were zenith pointing. Included in the files are the time variables base_time and time_offset. These follow the ARM time conventions. Base_time is the number seconds since January 1, 1970 at 00:00:00 for the first data point of the file and time_offset is

  19. ARM - Midlatitude Continental Convective Clouds Microwave Radiometer Profiler (jensen-mwr)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike

    2012-02-01

    A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment. These files contain brightness temperatures observed at Purcell during MC3E. The measurements were made with a 5 channel (22.235, 23.035, 23.835, 26.235, 30.000GHz) microwave radiometer at one minute intervals. The results have been separated into daily files and the day of observations is indicated in the file name. All observations were zenith pointing. Included in the files are the time variables base_time and time_offset. These follow the ARM time conventions. Base_time is the number seconds since January 1, 1970 at 00:00:00 for the first data point of the file and time_offset is the offset in seconds from base_time.

  20. Water Vapor Turbulence Profiles in Stationary Continental Convective Mixed Layers

    SciTech Connect (OSTI)

    Turner, D. D.; Wulfmeyer, Volker; Berg, Larry K.; Schween, Jan

    2014-10-08

    The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program’s Raman lidar at the ARM Southern Great Plains (SGP) site in north-central Oklahoma has collected water vapor mixing ratio (q) profile data more than 90% of the time since October 2004. Three hundred (300) cases were identified where the convective boundary layer was quasi-stationary and well-mixed for a 2-hour period, and q mean, variance, third order moment, and skewness profiles were derived from the 10-s, 75-m resolution data. These cases span the entire calendar year, and demonstrate that the q variance profiles at the mixed layer (ML) top changes seasonally, but is more related to the gradient of q across the interfacial layer. The q variance at the top of the ML shows only weak correlations (r < 0.3) with sensible heat flux, Deardorff convective velocity scale, and turbulence kinetic energy measured at the surface. The median q skewness profile is most negative at 0.85 zi, zero at approximately zi, and positive above zi, where zi is the depth of the convective ML. The spread in the q skewness profiles is smallest between 0.95 zi and zi. The q skewness at altitudes between 0.6 zi and 1.2 zi is correlated with the magnitude of the q variance at zi, with increasingly negative values of skewness observed lower down in the ML as the variance at zi increases, suggesting that in cases with larger variance at zi there is deeper penetration of the warm, dry free tropospheric air into the ML.

  1. The Midlatitude Continental Convective Clouds Experiment (MC3E)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jensen, M. P.; Petersen, W. A.; Bansemer, A.; Bharadwaj, N.; Carey, L. D.; Cecil, D. J.; Collis, S. M.; DelGenio, A. D.; Dolan, B.; Gerlach, J.; et al

    2015-12-18

    The Midlatitude Continental Convective Clouds Experiment (MC3E), a field program jointly led by the U.S. Department of Energy’s Atmospheric Radiation Measurement program and the NASA Global Precipitation Measurement (GPM) Mission, was conducted in south-central Oklahoma during April – May 2011. MC3E science objectives were motivated by the need to improve understanding of midlatitude continental convective cloud system lifecycles, microphysics, and GPM precipitation retrieval algorithms. To achieve these objectives a multi-scale surface- and aircraft-based in situ and remote sensing observing strategy was employed. A variety of cloud and precipitation events were sampled during the MC3E, of which results from three deepmore » convective events are highlighted. Vertical structure, air motions, precipitation drop-size distributions and ice properties were retrieved from multi-wavelength radar, profiler, and aircraft observations for an MCS on 11 May. Aircraft observations for another MCS observed on 20 May were used to test agreement between observed radar reflectivities and those calculated with forward-modeled reflectivity and microwave brightness temperatures using in situ particle size distributions and ice water content. Multi-platform observations of a supercell that occurred on 23 May allowed for an integrated analysis of kinematic and microphysical interactions. A core updraft of 25 ms-1 supported growth of hail and large rain drops. As a result, data collected during the MC3E campaign is being used in a number of current and ongoing research projects and is available through the DOE ARM and NASA data archives.« less

  2. The Midlatitude Continental Convective Clouds Experiment (MC3E)

    SciTech Connect (OSTI)

    Jensen, M. P.; Petersen, W. A.; Bansemer, A.; Bharadwaj, N.; Carey, L. D.; Cecil, D. J.; Collis, S. M.; DelGenio, A. D.; Dolan, B.; Gerlach, J.; Giangrande, S. E.; Heymsfield, A.; Heymsfield, G.; Kollias, P.; Lang, T. J.; Nesbitt, S. W.; Neumann, A.; Poellot, M.; Rutledge, S. A.; Schwaller, M.; Tokay, A.; Williams, C. R.; Wolff, D. B.; Xie, S.; Zipser, E. J.

    2015-12-18

    The Midlatitude Continental Convective Clouds Experiment (MC3E), a field program jointly led by the U.S. Department of Energy’s Atmospheric Radiation Measurement program and the NASA Global Precipitation Measurement (GPM) Mission, was conducted in south-central Oklahoma during April – May 2011. MC3E science objectives were motivated by the need to improve understanding of midlatitude continental convective cloud system lifecycles, microphysics, and GPM precipitation retrieval algorithms. To achieve these objectives a multi-scale surface- and aircraft-based in situ and remote sensing observing strategy was employed. A variety of cloud and precipitation events were sampled during the MC3E, of which results from three deep convective events are highlighted. Vertical structure, air motions, precipitation drop-size distributions and ice properties were retrieved from multi-wavelength radar, profiler, and aircraft observations for an MCS on 11 May. Aircraft observations for another MCS observed on 20 May were used to test agreement between observed radar reflectivities and those calculated with forward-modeled reflectivity and microwave brightness temperatures using in situ particle size distributions and ice water content. Multi-platform observations of a supercell that occurred on 23 May allowed for an integrated analysis of kinematic and microphysical interactions. A core updraft of 25 ms-1 supported growth of hail and large rain drops. As a result, data collected during the MC3E campaign is being used in a number of current and ongoing research projects and is available through the DOE ARM and NASA data archives.

  3. THE DOMINANCE OF NEUTRINO-DRIVEN CONVECTION IN CORE-COLLAPSE...

    Office of Scientific and Technical Information (OSTI)

    Third, buoyant driving is balanced by turbulent dissipation. Fourth, the convective ... Country of Publication: United States Language: English Subject: 79 ASTROPHYSICS, ...

  4. ARM Support for the Plains Elevated Convection at Night (AS-PECAN...

    Office of Scientific and Technical Information (OSTI)

    winds modulate bore structure, the role of these disturbances in the initiation, maintenance, and organization of deep convection, and their impact on the LLJ and SBL. *The LLJ ...

  5. The Mid-latitude Continental Convective Clouds (MC3E) Experiment...

    Office of Scientific and Technical Information (OSTI)

    Program Document: The Mid-latitude Continental Convective Clouds (MC3E) Experiment Final Campaign Report Citation Details In-Document Search Title: The Mid-latitude Continental ...

  6. CLIMATE CHANGE FUEL CELL PROGRAM UNITED STATES COAST GUARD AIR STATION CAPE COD BOURNE, MASSACHUSETTS

    SciTech Connect (OSTI)

    John K. Steckel Jr

    2004-06-30

    This report covers the first year of operation of a fuel cell power plant, installed by PPL Spectrum, Inc. (PPL) under contract with the United States Coast Guard (USCG), Research and Development Center (RDC). The fuel cell was installed at Air Station Cape Cod in Bourne, MA. The project had the support of the Massachusetts Technology Collaborative (MTC), the Department of Energy (DOE), and Keyspan Energy. PPL selected FuelCell Energy, Inc. (FCE) and its fuel cell model DFC{reg_sign}300 for the contract. Grant contributions were finalized and a contract between PPL and the USCG for the manufacture, installation, and first year's maintenance of the fuel cell was executed on September 24, 2001. As the prime contractor, PPL was responsible for all facets of the project. All the work was completed by PPL through various subcontracts, including the primary subcontract with FCE for the manufacture, delivery, and installation of the fuel cell. The manufacturing and design phases proceeded in a relatively timely manner for the first half of the project. However, during latter stages of manufacture and fuel cell testing, a variety of issues were encountered that ultimately resulted in several delivery delays, and a number of contract modifications. Final installation and field testing was completed in April and May 2003. Final acceptance of the fuel cell was completed on May 16, 2003. The fuel cell has operated successfully for more than one year. The unit achieved an availability rate of 96%, which exceeded expectations. The capacity factor was limited because the unit was set at 155 kW (versus a nameplate of 250 kW) due to the interconnection with the electric utility. There were 18 shutdowns during the first year and most were brief. The ability of this plant to operate in the island mode improved availability by 3 to 4%. Events that would normally be shutdowns were simply island mode events. The mean time between failure was calculated at 239 hours, or slightly less

  7. VARIABLE TIME DELAY MEANS

    DOE Patents [OSTI]

    Clemensen, R.E.

    1959-11-01

    An electrically variable time delay line is described which may be readily controlled simuitaneously with variable impedance matching means coupied thereto such that reflections are prevented. Broadly, the delay line includes a signal winding about a magnetic core whose permeability is electrically variable. Inasmuch as the inductance of the line varies directly with the permeability, the time delay and characteristic impedance of the line both vary as the square root of the permeability. Consequently, impedance matching means may be varied similariy and simultaneously w:th the electrically variable permeability to match the line impedance over the entire range of time delay whereby reflections are prevented.

  8. Variable Frequency Drives

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Marketing Toolkit The Benefits of Variable Frequency Drives (VFDs) VFDs help adjust motor speeds to match loads and improve efficiency while conserving energy. The benefits...

  9. Hydra-TH Extensions for Multispecies and Thermosolutal Convection

    SciTech Connect (OSTI)

    Stagg, Alan K

    2015-09-01

    This report describes the Consortium for Advanced Simulation of Light Water Reactors (CASL) work conducted for completion of the Thermal Hydraulics Methods (THM) Level 3 Milestone THM.CFD.P11.02: Hydra-TH Extensions for Multispecies and Thermosolutal Convection. A critical requirement for modeling reactor thermal hydraulics is to account for species transport within the fluid. In particular, this capability is needed for modeling transport and diffusion of boric acid within water for emergency, reactivity-control scenarios. To support this need, a species transport capability has been implemented in Hydra-TH for binary systems (for example, solute within a solvent). A species transport equation is solved for the species (solute) mass fraction, and both thermal and solutal buoyancy effects are handled with specification of a Boussinesq body force. Species boundary conditions can be specified with a Dirichlet condition on mass fraction or a Neumann condition on diffusion flux. To enable enhanced species/fluid mixing in turbulent flow, the molecular diffusivity for the binary system is augmented with a turbulent diffusivity in the species transport calculation. The new capabilities are demonstrated by comparison of Hydra-TH calculations to the analytic solution for a thermosolutal convection problem, and excellent agreement is obtained.

  10. An observational study of entrainment rate in deep convection

    SciTech Connect (OSTI)

    Guo, Xiaohao; Lu, Chunsong; Zhao, Tianliang; Zhang, Guang Jun; Liu, Yangang

    2015-09-22

    This study estimates entrainment rate and investigates its relationships with cloud properties in 156 deep convective clouds based on in-situ aircraft observations during the TOGA-COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment) field campaign over the western Pacific. To the authors’ knowledge, this is the first study on the probability density function of entrainment rate, the relationships between entrainment rate and cloud microphysics, and the effects of dry air sources on the calculated entrainment rate in deep convection from an observational perspective. Results show that the probability density function of entrainment rate can be well fitted by lognormal, gamma or Weibull distribution, with coefficients of determination being 0.82, 0.85 and 0.80, respectively. Entrainment tends to reduce temperature, water vapor content and moist static energy in cloud due to evaporative cooling and dilution. Inspection of the relationships between entrainment rate and microphysical properties reveals a negative correlation between volume-mean radius and entrainment rate, suggesting the potential dominance of homogeneous mechanism in the clouds examined. The entrainment rate and environmental water vapor content show similar tendencies of variation with the distance of the assumed environmental air to the cloud edges. Their variation tendencies are non-monotonic due to the relatively short distance between adjacent clouds.

  11. An observational study of entrainment rate in deep convection

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Guo, Xiaohao; Lu, Chunsong; Zhao, Tianliang; Zhang, Guang Jun; Liu, Yangang

    2015-09-22

    This study estimates entrainment rate and investigates its relationships with cloud properties in 156 deep convective clouds based on in-situ aircraft observations during the TOGA-COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment) field campaign over the western Pacific. To the authors’ knowledge, this is the first study on the probability density function of entrainment rate, the relationships between entrainment rate and cloud microphysics, and the effects of dry air sources on the calculated entrainment rate in deep convection from an observational perspective. Results show that the probability density function of entrainment rate can be well fitted by lognormal,more » gamma or Weibull distribution, with coefficients of determination being 0.82, 0.85 and 0.80, respectively. Entrainment tends to reduce temperature, water vapor content and moist static energy in cloud due to evaporative cooling and dilution. Inspection of the relationships between entrainment rate and microphysical properties reveals a negative correlation between volume-mean radius and entrainment rate, suggesting the potential dominance of homogeneous mechanism in the clouds examined. The entrainment rate and environmental water vapor content show similar tendencies of variation with the distance of the assumed environmental air to the cloud edges. Their variation tendencies are non-monotonic due to the relatively short distance between adjacent clouds.« less

  12. Convection causes enhanced magnetic turbulence in accretion disks in outburst

    SciTech Connect (OSTI)

    Hirose, Shigenobu; Blaes, Omer; Coleman, Matthew S. B.; Krolik, Julian H.; Sano, Takayoshi

    2014-05-20

    We present the results of local, vertically stratified, radiation magnetohydrodynamic (MHD) shearing box simulations of magneto-rotational instability (MRI) turbulence appropriate for the hydrogen ionizing regime of dwarf nova and soft X-ray transient outbursts. We incorporate the frequency-integrated opacities and equation of state for this regime, but neglect non-ideal MHD effects and surface irradiation, and do not impose net vertical magnetic flux. We find two stable thermal equilibrium tracks in the effective temperature versus surface mass density plane, in qualitative agreement with the S-curve picture of the standard disk instability model. We find that the large opacity at temperatures near 10{sup 4} K, a corollary of the hydrogen ionization transition, triggers strong, intermittent thermal convection on the upper stable branch. This convection strengthens the magnetic turbulent dynamo and greatly enhances the time-averaged value of the stress to thermal pressure ratio ?, possibly by generating vertical magnetic field that may seed the axisymmetric MRI, and by increasing cooling so that the pressure does not rise in proportion to the turbulent dissipation. These enhanced stress to pressure ratios may alleviate the order of magnitude discrepancy between the ?-values observationally inferred in the outburst state and those that have been measured from previous local numerical simulations of magnetorotational turbulence that lack net vertical magnetic flux.

  13. Special session: computational predictability of natural convection flows in enclosures

    SciTech Connect (OSTI)

    Christon, M A; Gresho, P M; Sutton, S B

    2000-08-14

    Modern thermal design practices often rely on a ''predictive'' simulation capability--although predictability is rarely quantified and often difficult to confidently achieve in practice. The computational predictability of natural convection in enclosures is a significant issue for many industrial thermal design problems. One example of this is the design for mitigation of optical distortion due to buoyancy-driven flow in large-scale laser systems. In many instances the sensitivity of buoyancy-driven enclosure flows can be linked to the presence of multiple bifurcation points that yield laminar thermal convective processes that transition from steady to various modes of unsteady flow. This behavior is brought to light by a problem as ''simple'' as a differentially-heated tall rectangular cavity (8:1 height/width aspect ratio) filled with a Boussinesq fluid with Pr = 0.71--which defines, at least partially, the focus of this special session. For our purposes, the differentially-heated cavity provides a virtual fluid dynamics laboratory.

  14. Characterization of Fuego for laminar and turbulent natural convection heat transfer.

    SciTech Connect (OSTI)

    Francis, Nicholas Donald, Jr. (,; .)

    2005-08-01

    A computational fluid dynamics (CFD) analysis is conducted for internal natural convection heat transfer using the low Mach number code Fuego. The flow conditions under investigation are primarily laminar, transitional, or low-intensity level turbulent flows. In the case of turbulent boundary layers at low-level turbulence or transitional Reynolds numbers, the use of standard wall functions no longer applies, in general, for wall-bounded flows. One must integrate all the way to the wall in order to account for gradients in the dependent variables in the viscous sublayer. Fuego provides two turbulence models in which resolution of the near-wall region is appropriate. These models are the v2-f turbulence model and a Launder-Sharma, low-Reynolds number turbulence model. Two standard geometries are considered: the annulus formed between horizontal concentric cylinders and a square enclosure. Each geometry emphasizes wall shear flow and complexities associated with turbulent or near turbulent boundary layers in contact with a motionless core fluid. Overall, the Fuego simulations for both laminar and turbulent flows compared well to measured data, for both geometries under investigation, and to a widely accepted commercial CFD code (FLUENT).

  15. Natural Convection and Boiling for Cooling SRP Reactors During Loss of Circulation Conditions

    SciTech Connect (OSTI)

    Buckner, M.R.

    2001-06-26

    This study investigated natural convection and boiling as a means of cooling SRP reactors in the event of a loss of circulation accident. These studies show that single phase natural convection cooling of SRP reactors in shutdown conditions with the present piping geometry is probably not feasible.

  16. Coupled interactions of organized deep convection over the tropical western pacific

    SciTech Connect (OSTI)

    Hong, X.; Raman, S.

    1996-04-01

    The relationship between sea surface temperature (SST) and deep convection is complex. In general, deep convection occurs more frequently and with more intensity as SSTs become higher. This theory assumes that the atmospheric stability is sufficiently reduced to allow the onset of moist convection. However, the amount and intensity of convection observed tends to decrease with increasing SST because very warm SSTs. A reason for such decrease is the enhancements to surface fluxes of heat and moisture out of the ocean surface because of the vertical overturning associated with deep convection. Early studies used the radiative-convective models of the atmosphere to examine the role of the convective exchange of heat and moisture in maintaining the vertical temperature profile. In this paper we use a Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) to simulate a squall line over a tropical ocean global atmosphere/coupled ocean atmosphere response experiment (TOGA/COARE) area and to investigate how the ocean cooling mechanisms associated with organized deep convection act to limit tropical SSTs.

  17. A shallow convection parameterization for the non-hydrostatic MM5 mesoscale model

    SciTech Connect (OSTI)

    Seaman, N.L.; Kain, J.S.; Deng, A.

    1996-04-01

    A shallow convection parameterization suitable for the Pennsylvannia State University (PSU)/National Center for Atmospheric Research nonhydrostatic mesoscale model (MM5) is being developed at PSU. The parameterization is based on parcel perturbation theory developed in conjunction with a 1-D Mellor Yamada 1.5-order planetary boundary layer scheme and the Kain-Fritsch deep convection model.

  18. Improving Convection Parameterization Using ARM Observations and NCAR Community Atmosphere Model

    SciTech Connect (OSTI)

    Zhang, Guang J

    2013-07-29

    Highlight of Accomplishments: We made significant contribution to the ASR program in this funding cycle by better representing convective processes in GCMs based on knowledge gained from analysis of ARM/ASR observations. In addition, our work led to a much improved understanding of the interaction among aerosol, convection, clouds and climate in GCMs.

  19. Environment and the Lifetime of Tropical Deep Convection in a Cloud-Permitting Regional Model Simulation

    SciTech Connect (OSTI)

    Hagos, Samson M.; Feng, Zhe; McFarlane, Sally A.; Leung, Lai-Yung R.

    2013-08-01

    By applying a cloud tracking algorithm to tropical convective systems simulated by a regional high resolution model, the study documents environmental conditions before and after convective systems are initiated over ocean and land by following them during their lifetime. The comparative roles of various environmental fields in affecting the lifetime of convection are also quantified. The statistics of lifetime, maximum area, propagation speed and direction of the simulated deep convection agrees well with geostationary satellite observations. Over ocean, convective systems enhance surface fluxes through the associated wind gusts as well as cooling and drying of the boundary layer. A significant relationship is found between the mean surface fluxes during their lifetime and the longevity of the systems which in turn is related to the initial intensity of the moist updraft and to a lesser extent upper level shear. Over land, on the other hand, convective activity suppresses surface fluxes through cloud cover and the lifetime of convection is related to the upper level shear during their lifetime and strength of the heat fluxes several hours before the initiation of convection. For systems of equal lifetime, those over land are significantly more intense than those over ocean especially during early stages of their lifetime.

  20. Joint seismic-geodynamic-mineral physical modelling of African geodynamics: A reconciliation of deep-mantle convection with surface geophysical constraints

    SciTech Connect (OSTI)

    Forte, A M; Quere, S; Moucha, R; Simmons, N A; Grand, S P; Mitrovica, J X; Rowley, D B

    2008-08-22

    Recent progress in seismic tomography provides the first complete 3-D images of the combined thermal and chemical anomalies that characterise the unique deep mantle structure below the African continent. With these latest tomography results we predict flow patterns under Africa that reveal a large-scale, active hot upwelling, or superplume, below the western margin of Africa under the Cape Verde Islands. The scale and dynamical intensity of this West African superplume (WASP) is comparable to that of the south African superplume (SASP) that has long been assumed to dominate the flow dynamics under Africa. On the basis of this new tomography model, we find the dynamics of the SASP is strongly controlled by chemical contributions to deep mantle buoyancy that significantly compensate its thermal buoyancy. In contrast, the WASP appears to be entirely dominated by thermal buoyancy. New calculations of mantle convection incorporating these two superplumes reveal that the plate-driving forces due to the flow generated by the WASP is as strong as that due to the SASP. We find that the chemical buoyancy of the SASP exerts a strong stabilising control on the pattern and amplitude of shallow mantle flow in the asthenosphere below the southern half of the African plate. The asthenospheric flow predictions provide the first high resolution maps of focussed upwellings that lie below the major centres of Late Cenozoic volcanism, including the Kenya domes and Hoggar massif that lies above a remnant plume head in the upper mantle. Inferences of sublithospheric deformation from seismic anisotropy data are shown to be sensitive to the contributions of chemical buoyancy in the SASP.

  1. Numerical analysis of heat transfer by conduction and natural convection in loose-fill fiberglass insulation--effects of convection on thermal performance

    SciTech Connect (OSTI)

    Delmas, A.A.; Wilkes, K.E.

    1992-04-01

    A two-dimensional code for solving equations of convective heat transfer in porous media is used to analyze heat transfer by conduction and convection in the attic insulation configuration. The particular cases treated correspond to loose-fill fiberglass insulation, which is characterized by high porosity and air permeability. The effects of natural convection on the thermal performance of the insulation are analyzed for various densities, permeabilities, and thicknesses of insulation. With convection increasing the total heat transfer through the insulation, the thermal resistance was found to decrease as the temperature difference across the insulating material increases. The predicted results for the thermal resistance are compared with data obtained in the large-scale climate simulator at the Roof Research Center using the attic test module, where the same phenomenon has already been observed. The way the wood joists within the insulation influence the start of convection is studied for differing thermophysical and dynamic properties of the insulating material. The presence of wood joists induces convection at a lower temperature difference.

  2. ARM - Midlatitude Continental Convective Clouds (jensen-sonde...

    Office of Scientific and Technical Information (OSTI)

    of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. ...

  3. The structure and dynamics of patterns of Benard convection cells

    SciTech Connect (OSTI)

    Rivier, N. Imperial Coll. of Science and Technology, London . Blackett Lab. Lausanne Univ. . Inst. de Physique Experimentale)

    1990-08-01

    Benard-Marangoni convection, in containers with large aspect ratio, exhibits space-filling cellular structures, highly deformable, but crystallized. They contain dislocations and grain boundaries generated and moved by elementary topological transformations, and are subjected to a weak shear stress due to the earth's rotation. The cellular structure and its fluctuations are analyzed from a crystallographic viewpoint, by using two complementary approaches. One is a global analysis of cellular structures in cylindrical symmetry. Their structural stability and defect pattern are obtained as topological mode-locking of a continuous structural parameter. The other, a local, molecular dynamics of the cells, gives a realistic parametrization of the forces and the transformations by generalizing the Voronoi cell construction in one extra dimension. 23 refs., 8 figs.

  4. Operating temperatures for a convectively cooled recessed incandescent light fixture

    SciTech Connect (OSTI)

    Yarbrough, D.W.; Toor, I.

    1980-12-01

    Test results are given for the operation of a recessed incandescent light fixture intended for residential use. The fixture is labeled for use in direct contact with attic thermal insulation. Temperature control of the powered fixture is provided by convective heat transfer from the ceiling side of the fixture. The fixture was operated at power levels up to two times the rated power of 75 watts and under thermal insulations up to R-40. In all operating configurations tested the fixture surface in contact with attic insulation was found to be less than 175/sup 0/C. The observed surface temperatures are judged to be safe for operation in contact with loose-fill or batt-type insulations. It was observed that the power leads inside one fixture configuration are exposed to temperatures as high as 168/sup 0/C. The electrical insulation could, therefore, have a limited life. The properties of the internal fixture wiring were not, however, studied in detail.

  5. Understanding Biomass Feedstock Variability

    SciTech Connect (OSTI)

    Kevin L. Kenney; William A. Smith; Garold L. Gresham; Tyler L. Westover

    2013-01-01

    If the singular goal of biomass logistics and the design of biomass feedstock supply systems is to reduce the per ton supply cost of biomass, these systems may very well develop with ultimate unintended consequences of highly variable and reduced quality biomass feedstocks. This paper demonstrates that due to inherent species variabilities, production conditions, and differing harvest, collection, and storage practices, this is a very real scenario that biomass producers and suppliers as well as conversion developers should be aware of. Biomass feedstock attributes of ash, carbohydrates, moisture, and particle morphology will be discussed. We will also discuss specifications for these attributes, inherent variability of these attributes in biomass feedstocks, and approaches and solutions for reducing variability for improving feedstock quality.

  6. Understanding Biomass Feedstock Variability

    SciTech Connect (OSTI)

    Kevin L. Kenney; Garold L. Gresham; William A. Smith; Tyler L. Westover

    2013-01-01

    If the singular goal of biomass logistics and the design of biomass feedstock supply systems is to reduce the per-ton supply cost of biomass, these systems may very well develop with ultimate unintended consequences of highly variable and reduced quality biomass feedstocks. This paper demonstrates that, due to inherent species variabilities, production conditions and differing harvest, collection and storage practices, this is a very real scenario that biomass producers and suppliers as well as conversion developers should be aware of. Biomass feedstock attributes of ash, carbohydrates, moisture and particle morphology will be discussed. We will also discuss specifications for these attributes, inherent variability of these attributes in biomass feedstocks, and approaches and solutions for reducing variability for improving feedstock quality.

  7. VARIABLE-THROW CAM

    DOE Patents [OSTI]

    Godsil, E.C.; Robinson, E.Y.

    1963-07-16

    A variable-throw cam comprising inner and outer eccentric sleeves which are adjustably locked together is described. The cam throw is varied by unlocking the inner and outer sleeves, rotating the outer sleeve relative to the inner one until the desired throw is obtained, and locking the sleeves together again. The cam is useful in applications wherein a continuously-variable throw is required, e.g., ram-and-die pressing operations, cyclic fatigue testing of materials, etc. (AEC)

  8. Research Highlight

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    upward motion of the large-scale circulation. It allows convective available potential energy, or CAPE, to accumulate from surface processes before convection occurs and links...

  9. Convection in X-ray Bursts Michael Zingale Stony Brook University

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Convection in X-ray Bursts Michael Zingale Stony Brook University in collaboration with Ann Almgren, John Bell, Andy Nonaka (LBL); Chris Malone (LANL), Stan Woosley (UCSC) Supported by DOE/Office of Nuclear Physics, DE-FG02-06ER41448 and DE-FG02-87ER40317 to Stony Brook, and NSF award AST-1211563. Computer time: National Energy Research Scientific Computing Center (Office of Science, DOE DE-AC02-05CH11231) Convection in Astrophysics ● Evolution of many stellar systems dominated by convective

  10. Variable thrust cartridge

    DOE Patents [OSTI]

    Taleyarkhan, Rusi P.

    2000-11-07

    The present invention is a variable thrust cartridge comprising a water-molten aluminum reaction chamber from which a slug is propelled. The cartridge comprises a firing system that initiates a controlled explosion from the reaction chamber. The explosive force provides a thrust to a slug, preferably contained within the cartridge.

  11. Variable capacity gasification burner

    SciTech Connect (OSTI)

    Saxon, D.I.

    1985-03-05

    A variable capacity burner that may be used in gasification processes, the burner being adjustable when operating in its intended operating environment to operate at two different flow capacities, with the adjustable parts being dynamically sealed within a statically sealed structural arrangement to prevent dangerous blow-outs of the reactants to the atmosphere.

  12. Convective heat transfer correlations for fenestration glazing cavities: A review

    SciTech Connect (OSTI)

    Zhao, Y.; Curcija, D.; Goss, W.P.

    1999-07-01

    Convective heat transfer in insulated glazing unit (IGU) cavities is a major component of the overall heat transfer in fenestration systems. Accurately quantifying the heat-transfer coefficient within the cavity is of great significance in calculating the center-of-glass U factor, the edge-of-glass U factor, and therefore the overall U factor. Over the past 40 years, along with the rapid development of experimental techniques and numerical methods as well as the powerful computer systems, the heat-transfer correlations have been updated either from experimental data or from numerical data from time to time. The literature reviewed here covers correlations based on simplified analytical studies, on the experimental data, and on the numerical results. In addition, most of the correlation equations cover the typical design range of fenestration glazing cavities, e.g., Ra < 20,000. Inconsistencies and discrepancies existing between different experimental observations, and between derived numerical/analytical correlations and available experimental data, are discussed.

  13. Radial convection of finite ion temperature, high amplitude plasma blobs

    SciTech Connect (OSTI)

    Wiesenberger, M. Kendl, A.; Madsen, J.

    2014-09-15

    We present results from simulations of seeded blob convection in the scrape-off-layer of magnetically confined fusion plasmas. We consistently incorporate high fluctuation amplitude levels and finite Larmor radius (FLR) effects using a fully nonlinear global gyrofluid model. This is in line with conditions found in tokamak scrape-off-layers (SOL) regions. Varying the ion temperature, the initial blob width, and the initial amplitude, we found an FLR dominated regime where the blob behavior is significantly different from what is predicted by cold-ion models. The transition to this regime is very well described by the ratio of the ion gyroradius to the characteristic gradient scale length of the blob. We compare the global gyrofluid model with a partly linearized local model. For low ion temperatures, we find that simulations of the global model show more coherent blobs with an increased cross-field transport compared to blobs simulated with the local model. The maximal blob amplitude is significantly higher in the global simulations than in the local ones. When the ion temperature is comparable to the electron temperature, global blob simulations show a reduced blob coherence and a decreased cross-field transport in comparison with local blob simulations.

  14. Explicit simulation of a midlatitude Mesoscale Convective System

    SciTech Connect (OSTI)

    Alexander, G.D.; Cotton, W.R.

    1996-04-01

    We have explicitly simulated the mesoscale convective system (MCS) observed on 23-24 June 1985 during PRE-STORM, the Preliminary Regional Experiment for the Stormscale Operational and Research and Meterology Program. Stensrud and Maddox (1988), Johnson and Bartels (1992), and Bernstein and Johnson (1994) are among the researchers who have investigated various aspects of this MCS event. We have performed this MCS simulation (and a similar one of a tropical MCS; Alexander and Cotton 1994) in the spirit of the Global Energy and Water Cycle Experiment Cloud Systems Study (GCSS), in which cloud-resolving models are used to assist in the formulation and testing of cloud parameterization schemes for larger-scale models. In this paper, we describe (1) the nature of our 23-24 June MCS dimulation and (2) our efforts to date in using our explicit MCS simulations to assist in the development of a GCM parameterization for mesoscale flow branches. The paper is organized as follows. First, we discuss the synoptic situation surrounding the 23-24 June PRE-STORM MCS followed by a discussion of the model setup and results of our simulation. We then discuss the use of our MCS simulation. We then discuss the use of our MCS simulations in developing a GCM parameterization for mesoscale flow branches and summarize our results.

  15. Compactification of Patterns by a Singular Convection or Stress

    SciTech Connect (OSTI)

    Rosenau, Philip

    2007-12-07

    A wide variety of propagating disturbances in physical systems are described by equations whose solutions lack a sharp propagating front. We demonstrate that presence of particular nonlinearities may induce such fronts. To exemplify this idea, we study both dissipative u{sub t}+{partial_derivative}{sub x}f(u)=u{sub xx} and dispersive u{sub t}+{partial_derivative}{sub x}f(u)+u{sub xxx}=0 patterns, and show that a weakly singular convection f(u)=-u{sup {alpha}}+u{sup m}, 0<{alpha}<1

  16. Theoretical analysis of solar-driven natural convection energy conversion systems

    SciTech Connect (OSTI)

    Jacobs, E.W.; Lasier, D.D.

    1984-01-01

    This report presents a theoretical study of solar-powered natural convection tower (chimney) performance. Both heated and cooled towers are analyzed; the latter uses evaporating water as the cooling mechanism. The results, which are applicable to any open-cycle configuration, show that the ideal conversion efficiencies of both heated and cooled natural convection towers are linear functions of height. The performance of a heated tower in an adiabatic atmosphere ideally approaches the Carnot efficiency limit of approx. = 3.4%/km (1.0%/1000 ft). Including water pumping requirements, the ideal limit to cooled tower performance is approx. = 2.75%/km (0.85%/1000 ft). Ambient atmospheric conditions such as vertical temperature gradient (lapse rate) and relative humidity can have significantly adverse effects on natural convection tower performance. The combined effects of lapse rate and ambient relative humidity are especially important to cooled natural convection towers.

  17. Mixed convection radiative flow of three dimensional Maxwell fluid over an inclined stretching sheet in presence of thermophoresis and convective condition

    SciTech Connect (OSTI)

    Ashraf, M. Bilal; Hayat, T.; Shehzad, S. A.; Alsaedi, A.

    2015-02-15

    Three dimensional radiative flow of Maxwell fluid over an inclined stretching surface with convective boundary condition is investigated. Heat and mass transfer analysis is taken into account with thermophoresis effects. Similarity transformations are utilized to reduce the partial differential equations into ordinary differential equations. Series solutions of velocity, temperature and concentration are developed. Influence of different parameters Biot number, therrmophoretic parameter, Deborah number, ratio parameter, inclined stretching angle, radiation parameter, mixed convection parameter and concentration buoyancy parameter on the non-dimensional velocity components, temperature and concentration are plotted and discussed in detail. Physical quantities of interests are tabulated and examined.

  18. Mixed convection heat transfer from thermal sources mounted on horizontal and vertical surfaces

    SciTech Connect (OSTI)

    Tewari, S.S.; Jaluria, Y. )

    1990-11-01

    An experimental study is carried out on the fundamental aspects of the conjugate, mixed convective heat transfer from two finite width heat sources, which are of negligible thickness, have a uniform heat flux input at the surface, and are located on a flat plate in a horizontal or the vertical orientation. The heat sources are wide in the transverse direction and, therefore, a two-dimensional flow circumstance is simulated. The mixed convection parameter is varied over a fairly wide range to include the buoyancy-dominated and the mixed convection regimes. The circumstances of pure natural convection are also investigated. The convective mechanisms have been studied in detail by measuring the surface temperatures and determining the heat transfer coefficients for the two heated strips, which represent isolated thermal sources. Experimental results indicate that a stronger upstream heat source causes an increase in the surface temperature of a relatively weaker heat source, located downstream, by reducing it convective heat transfer coefficient. The influence of the upstream source is found to be strongly dependent on the surface orientation, especially in the pure natural convection and the buoyancy dominated regimes. The two heat sources are found to be essentially independent on the surface orientation, especially in the pure natural convection and the buoyancy dominated regimes. The two heat sources are found to be essentially independent of each other, in terms of thermal effects, at a separation distance of more than about three strip widths for both the orientations. The results obtained are relevant to many engineering applications, such as the cooling of electronic systems, positioning of heating elements in furnaces, and safety considerations in enclosure fires.

  19. Transport Induced by Large Scale Convective Structures in a Dipole-Confined Plasma

    SciTech Connect (OSTI)

    Grierson, B. A.; Mauel, M. E.; Worstell, M. W.; Klassen, M.

    2010-11-12

    Convective structures characterized by ExB motion are observed in a dipole-confined plasma. Particle transport rates are calculated from density dynamics obtained from multipoint measurements and the reconstructed electrostatic potential. The calculated transport rates determined from the large-scale dynamics and local probe measurements agree in magnitude, show intermittency, and indicate that the particle transport is dominated by large-scale convective structures.

  20. On the Features of Radiative and Convective Regimes Under the Cumulus Cloudiness

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    On the Features of Radiative and Convective Regimes Under the Cumulus Cloudiness B. M. Koprov, V. M. Koprov, G. S. Golitsyn A.M. Oboukhov Institute of Atmospheric Physics Moscow, Russia E. N. Kadygrov, A. V. Koldaev Central Aerological Observatory Dolgoprudny, Russia Introduction The study of instant temperature field transformation, convective and radiative regime perturbation within the layer of 0 to 650 m was fulfilled as caused by cloud modulation of solar radiation flux. It was made within

  1. HYDRODYNAMIC SIMULATIONS OF H ENTRAINMENT AT THE TOP OF He-SHELL FLASH CONVECTION

    SciTech Connect (OSTI)

    Woodward, Paul R.; Lin, Pei-Hung; Herwig, Falk E-mail: fherwig@uvic.ca

    2015-01-01

    We present the first three-dimensional, fully compressible gas-dynamics simulations in 4? geometry of He-shell flash convection with proton-rich fuel entrainment at the upper boundary. This work is motivated by the insufficiently understood observed consequences of the H-ingestion flash in post-asymptotic giant branch (post-AGB) stars (Sakurai's object) and metal-poor AGB stars. Our investigation is focused on the entrainment process at the top convection boundary and on the subsequent advection of H-rich material into deeper layers, and we therefore ignore the burning of the proton-rich fuel in this study. We find that for our deep convection zone, coherent convective motions of near global scale appear to dominate the flow. At the top boundary convective shear flows are stable against Kelvin-Helmholtz instabilities. However, such shear instabilities are induced by the boundary-layer separation in large-scale, opposing flows. This links the global nature of thick shell convection with the entrainment process. We establish the quantitative dependence of the entrainment rate on grid resolution. With our numerical technique, simulations with 1024{sup 3} cells or more are required to reach a numerical fidelity appropriate for this problem. However, only the result from the 1536{sup 3} simulation provides a clear indication that we approach convergence with regard to the entrainment rate. Our results demonstrate that our method, which is described in detail, can provide quantitative results related to entrainment and convective boundary mixing in deep stellar interior environments with very stiff convective boundaries. For the representative case we study in detail, we find an entrainment rate of 4.38 1.48 10{sup 13} M {sub ?} s{sup 1}.

  2. Sensitivity of Boundary-layer and Deep Convective Cloud Simulations to

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Vertical Resolution Sensitivity of Boundary-layer and Deep Convective Cloud Simulations to Vertical Resolution Cheng, Anning Langley Research Center Xu, Kuan-Man NASA Langley Research Center Category: Modeling This study investigates the effects of vertical resolution on the simulation of boundary-layer and deep convective clouds using a cloud resolving model (CRM). A CRM usually uses a vertical grid spacing less than 100 m to simulate boundary layer clouds such as shallow cumuli and

  3. South Atlantic OCS area living marine resources study. Volume II: an investigation of live bottom habitats north of Cape Fear, North Carolina. Final report

    SciTech Connect (OSTI)

    Not Available

    1981-10-01

    The major objectives of this study were to (1) characterize benthic and nektonic communities associated with representative live bottom habitats on the continental shelf of the South Atlantic Bight, and (2) evaluate factors which might influence these communities, particularly the potential for impact by offshore oil and gas activities. The report describes three study sites at the edge of the continental shelf in a 55-100m depth zone, near Cape Fear, North Carolina.

  4. Film condensation of saturated and superheated vapors along isothermal vertical surfaces in mixed convection

    SciTech Connect (OSTI)

    Winkler, C.M.; Chen, T.S.; Minkowycz, W.J.

    1999-09-01

    An analysis for condensation from an isothermal vertical flat plate in mixed convection is reported. The entire mixed convection regime is divided into two regions. One region covers the forced-convection-dominated regime, and the other covers the free-convection-dominated regime. The governing system of equations is first transformed into a dimensionless form by the nonsimilar transformation, separately for each regime, and then solved using the local nonsimilarity method along with a finite difference scheme. Two nonsimilarity parameters are introduced. The parameter {xi}{sub f} = Gr{sub x}/Re{sub x}{sup 2} characterizes the effect of buoyancy force on forced convection, while the parameter {xi}{sub n} = Re{sub x}/Gr{sub x}{sup 1/2} characterizes the effect of forced flow on free convection. Numerical results for pure steam and refrigerant R-134a are presented for both saturated and superheated cases. It is found that the buoyancy force significantly increases the wall shear stress and condensate mass flux. To a lesser degree, the buoyancy force also increases the wall heat flux. Superheating is found to have an insignificant effect on wall heat flux for a pure vapor.

  5. Variable depth core sampler

    DOE Patents [OSTI]

    Bourgeois, Peter M.; Reger, Robert J.

    1996-01-01

    A variable depth core sampler apparatus comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member.

  6. Variable depth core sampler

    DOE Patents [OSTI]

    Bourgeois, P.M.; Reger, R.J.

    1996-02-20

    A variable depth core sampler apparatus is described comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member. 7 figs.

  7. Variable percentage sampler

    DOE Patents [OSTI]

    Miller, Jr., William H.

    1976-01-01

    A remotely operable sampler is provided for obtaining variable percentage samples of nuclear fuel particles and the like for analyses. The sampler has a rotating cup for a sample collection chamber designed so that the effective size of the sample inlet opening to the cup varies with rotational speed. Samples of a desired size are withdrawn from a flowing stream of particles without a deterrent to the flow of remaining particles.

  8. Variable laser attenuator

    DOE Patents [OSTI]

    Foltyn, Stephen R.

    1988-01-01

    The disclosure relates to low loss, high power variable attenuators comprng one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength.

  9. Variable laser attenuator

    DOE Patents [OSTI]

    Foltyn, S.R.

    1987-05-29

    The disclosure relates to low loss, high power variable attenuators comprising one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength. 9 figs.

  10. CALIBRATION OF THE MIXING-LENGTH THEORY FOR CONVECTIVE WHITE DWARF ENVELOPES

    SciTech Connect (OSTI)

    Tremblay, P.-E.; Ludwig, H.-G.; Freytag, B.; Fontaine, G.; Brassard, P.; Steffen, M.

    2015-02-01

    A calibration of the mixing-length parameter in the local mixing-length theory (MLT) is presented for the lower part of the convection zone in pure-hydrogen-atmosphere white dwarfs. The parameterization is performed from a comparison of three-dimensional (3D) CO5BOLD simulations with a grid of one-dimensional (1D) envelopes with a varying mixing-length parameter. In many instances, the 3D simulations are restricted to the upper part of the convection zone. The hydrodynamical calculations suggest, in those cases, that the entropy of the upflows does not change significantly from the bottom of the convection zone to regions immediately below the photosphere. We rely on this asymptotic entropy value, characteristic of the deep and adiabatically stratified layers, to calibrate 1D envelopes. The calibration encompasses the convective hydrogen-line (DA) white dwarfs in the effective temperature range 6000 ≤ T {sub eff} (K) ≤15, 000 and the surface gravity range 7.0 ≤ log g ≤ 9.0. It is established that the local MLT is unable to reproduce simultaneously the thermodynamical, flux, and dynamical properties of the 3D simulations. We therefore propose three different parameterizations for these quantities. The resulting calibration can be applied to structure and envelope calculations, in particular for pulsation, chemical diffusion, and convective mixing studies. On the other hand, convection has no effect on the white dwarf cooling rates until there is a convective coupling with the degenerate core below T {sub eff} ∼ 5000 K. In this regime, the 1D structures are insensitive to the MLT parameterization and converge to the mean 3D results, hence they remain fully appropriate for age determinations.

  11. Variable leak gas source

    DOE Patents [OSTI]

    Henderson, Timothy M.; Wuttke, Gilbert H.

    1977-01-01

    A variable leak gas source and a method for obtaining the same which includes filling a quantity of hollow glass micro-spheres with a gas, storing said quantity in a confined chamber having a controllable outlet, heating said chamber above room temperature, and controlling the temperature of said chamber to control the quantity of gas passing out of said controllable outlet. Individual gas filled spheres may be utilized for calibration purposes by breaking a sphere having a known quantity of a known gas to calibrate a gas detection apparatus.

  12. Variable Valve Actuation

    SciTech Connect (OSTI)

    Jeffrey Gutterman; A. J. Lasley

    2008-08-31

    Many approaches exist to enable advanced mode, low temperature combustion systems for diesel engines - such as premixed charge compression ignition (PCCI), Homogeneous Charge Compression Ignition (HCCI) or other HCCI-like combustion modes. The fuel properties and the quantity, distribution and temperature profile of air, fuel and residual fraction in the cylinder can have a marked effect on the heat release rate and combustion phasing. Figure 1 shows that a systems approach is required for HCCI-like combustion. While the exact requirements remain unclear (and will vary depending on fuel, engine size and application), some form of substantially variable valve actuation is a likely element in such a system. Variable valve actuation, for both intake and exhaust valve events, is a potent tool for controlling the parameters that are critical to HCCI-like combustion and expanding its operational range. Additionally, VVA can be used to optimize the combustion process as well as exhaust temperatures and impact the after treatment system requirements and its associated cost. Delphi Corporation has major manufacturing and product development and applied R&D expertise in the valve train area. Historical R&D experience includes the development of fully variable electro-hydraulic valve train on research engines as well as several generations of mechanical VVA for gasoline systems. This experience has enabled us to evaluate various implementations and determine the strengths and weaknesses of each. While a fully variable electro-hydraulic valve train system might be the 'ideal' solution technically for maximum flexibility in the timing and control of the valve events, its complexity, associated costs, and high power consumption make its implementation on low cost high volume applications unlikely. Conversely, a simple mechanical system might be a low cost solution but not deliver the flexibility required for HCCI operation. After modeling more than 200 variations of the

  13. Stability and error analysis of nodal expansion method for convection-diffusion equation

    SciTech Connect (OSTI)

    Deng, Z.; Rizwan-Uddin; Li, F.; Sun, Y.

    2012-07-01

    The development, and stability and error analyses of nodal expansion method (NEM) for one dimensional steady-state convection diffusion equation is presented. Following the traditional procedure to develop NEM, the discrete formulation of the convection-diffusion equation, which is similar to the standard finite difference scheme, is derived. The method of discrete perturbation analysis is applied to this discrete form to study the stability of the NEM. The scheme based on the NEM is found to be stable for local Peclet number less than 4.644. A maximum principle is proved for the NEM scheme, followed by an error analysis carried out by applying the Maximum principle together with a carefully constructed comparison function. The scheme for the convection diffusion equation is of second-order. Numerical experiments are carried and the results agree with the conclusions of the stability and error analyses. (authors)

  14. CYCLIC THERMAL SIGNATURE IN A GLOBAL MHD SIMULATION OF SOLAR CONVECTION

    SciTech Connect (OSTI)

    Cossette, Jean-Francois; Charbonneau, Paul; Smolarkiewicz, Piotr K.

    2013-11-10

    Global magnetohydrodynamical simulations of the solar convection zone have recently achieved cyclic large-scale axisymmetric magnetic fields undergoing polarity reversals on a decadal time scale. In this Letter, we show that these simulations also display a thermal convective luminosity that varies in-phase with the magnetic cycle, and trace this modulation to deep-seated magnetically mediated changes in convective flow patterns. Within the context of the ongoing debate on the physical origin of the observed 11 yr variations in total solar irradiance, such a signature supports the thesis according to which all, or part, of the variations on decadal time scales and longer could be attributed to a global modulation of the Sun's internal thermal structure by magnetic activity.

  15. Meridional flow in the solar convection zone. I. Measurements from gong data

    SciTech Connect (OSTI)

    Kholikov, S.; Serebryanskiy, A.; Jackiewicz, J.

    2014-04-01

    Large-scale plasma flows in the Sun's convection zone likely play a major role in solar dynamics on decadal timescales. In particular, quantifying meridional motions is a critical ingredient for understanding the solar cycle and the transport of magnetic flux. Because the signal of such features can be quite small in deep solar layers and be buried in systematics or noise, the true meridional velocity profile has remained elusive. We perform time-distance helioseismology measurements on several years worth of Global Oscillation Network Group Doppler data. A spherical harmonic decomposition technique is applied to a subset of acoustic modes to measure travel-time differences to try to obtain signatures of meridional flows throughout the solar convection zone. Center-to-limb systematics are taken into account in an intuitive yet ad hoc manner. Travel-time differences near the surface that are consistent with a poleward flow in each hemisphere and are similar to previous work are measured. Additionally, measurements in deep layers near the base of the convection zone suggest a possible equatorward flow, as well as partial evidence of a sign change in the travel-time differences at mid-convection zone depths. This analysis on an independent data set using different measurement techniques strengthens recent conclusions that the convection zone may have multiple 'cells' of meridional flow. The results may challenge the common understanding of one large conveyor belt operating in the solar convection zone. Further work with helioseismic inversions and a careful study of systematic effects are needed before firm conclusions of these large-scale flow structures can be made.

  16. VARIABLE TIME-INTERVAL GENERATOR

    DOE Patents [OSTI]

    Gross, J.E.

    1959-10-31

    This patent relates to a pulse generator and more particularly to a time interval generator wherein the time interval between pulses is precisely determined. The variable time generator comprises two oscillators with one having a variable frequency output and the other a fixed frequency output. A frequency divider is connected to the variable oscillator for dividing its frequency by a selected factor and a counter is used for counting the periods of the fixed oscillator occurring during a cycle of the divided frequency of the variable oscillator. This defines the period of the variable oscillator in terms of that of the fixed oscillator. A circuit is provided for selecting as a time interval a predetermined number of periods of the variable oscillator. The output of the generator consists of a first pulse produced by a trigger circuit at the start of the time interval and a second pulse marking the end of the time interval produced by the same trigger circuit.

  17. A scaling analysis of thermoacoustic convection in a zero-gravity environment

    SciTech Connect (OSTI)

    Krane, R.J.; Parang, M.

    1982-01-01

    This paper presents a scaling analysis of a one-dimensional thermoacoustic convection heat transfer process in a zero-gravity environment. The relative importance of the terms in the governing equations is discussed for different time scales without attempting to solve the equations. The scaling analysis suggests certain generalizations that can be made in this class of heat transfer problems.

  18. New bounded skew central difference scheme. Part 2: Application to natural convection in an eccentric annulus

    SciTech Connect (OSTI)

    Moukalled, F.; Darwish, M.

    1997-01-01

    The bounded skew central difference scheme (NVF SCDS) is used to study numerically the combined effect of vertical ({epsilon}{sub y}) and horizontal ({epsilon}{sub x}) eccentricities on natural convection in an annulus between a heated horizontal cylinder and its square enclosure. Four Rayleigh numbers (Ra = 10{sup 3}, 10{sup 4}, 10{sup 5}, and 10{sup 6}), three aspect ratios (R/L = 0.1, 0.2, and 0.3), and eccentricity values ranging from {minus}0.3 to 0.3 are considered. At constant enclosure aspect ratio, the total heat transfer increases with increasing Rayleigh number. For constant Rayleigh-number values, convection contribution to total heat transfer decreases with increasing values of R/L. For conduction-dominated flows, heat transfer increases with increasing {vert_bar}{epsilon}{sub y}{vert_bar} and/or {vert_bar}{epsilon}{sub x}{vert_bar}. For convection-dominated flows, heat transfer increases with decreasing {epsilon}{sub y} for {epsilon}{sub y} < 0, decreases with increasing {epsilon}{sub y} for {epsilon}{sub y} > 0, and decreases with decreasing {epsilon}{sub x} for {epsilon}{sub x} < 0. For the case when conduction and convection are of equal importance, there is a critical {epsilon}{sub x} for which the total heat transfer is minimum.

  19. What Goes Up Must Come Down: The Lifecycle of Convective Clouds (492nd Brookhaven Lecture)

    SciTech Connect (OSTI)

    Jensen, Michael

    2014-02-19

    Some clouds look like cotton balls and others like anvils. Some bring rain, some snow and sleet, and others, just shade. But, whether big and billowy or dark and stormy, clouds affect far more than the weather each day. Armed with measurements of clouds’ updrafts and downdrafts—which resemble airflow in a convection oven—and many other atmospheric interactions, scientists from Brookhaven Lab and other institutions around the world are developing models that are crucial for understanding Earth’s climate and forecasting future climate change. During his lecture, Dr. Jensen provides an overview of the importance of clouds in the Earth’s climate system before explaining how convective clouds form, grow, and dissipate. His discussion includes findings from the Midlatitude Continental Convective Clouds Experiment (MC3E), a major collaborative experiment between U.S. Department of Energy (DOE) and NASA scientists to document precipitation, clouds, winds, and moisture in 3-D for a holistic view of convective clouds and their environment.

  20. Compact fluorescent lamp using horizontal and vertical insulating septums and convective venting geometry

    DOE Patents [OSTI]

    Siminovitch, Michael

    1998-01-01

    A novel design for a compact fluorescent lamp, including a lamp geometry which will increase light output and efficacy of the lamp in a base down operating position by providing horizontal and vertical insulating septums positioned in the ballast compartment of the lamp to provide a cooler coldspot. Selective convective venting provides additional cooling of the ballast compartment.

  1. Compact fluorescent lamp using horizontal and vertical insulating septums and convective venting geometry

    DOE Patents [OSTI]

    Siminovitch, M.

    1998-02-10

    A novel design is described for a compact fluorescent lamp, including a lamp geometry which will increase light output and efficacy of the lamp in a base down operating position by providing horizontal and vertical insulating septums positioned in the ballast compartment of the lamp to provide a cooler coldspot. Selective convective venting provides additional cooling of the ballast compartment. 9 figs.

  2. Measurement of gas temperature and convection velocity profiles in a dc atmospheric glow discharge

    SciTech Connect (OSTI)

    Stepaniuk, Vadim P.; Ioppolo, Tindaro; Oetuegen, M. Volkan; Sheverev, Valery A.

    2007-12-15

    Gas temperature and convective velocity distributions are presented for an unconfined glow discharge in air at atmospheric pressure, with electric currents ranging between 30 and 92 mA. The vertically oriented discharge was formed between a pin anode (top) and an extended cathode. The temperature and velocity profiles were measured using laser-induced Rayleigh scattering and laser Doppler anemometry techniques, respectively. The temperature field exhibited a conical shape with the radius of hot temperature zone increasing toward the anode. A maximum temperature of 2470 K was observed on the discharge axis with the discharge current of 92 mA. Air velocity measurements around the discharge demonstrated that the shape and magnitude of the temperature field are strongly affected by natural convection. Estimates indicate that convective losses may account for more than 50% of the power input into the positive column of the discharge. The measured temperature fields and convective velocity profiles provide a set of data that is important for the evaluation of dc atmospheric glow discharges in various applications such as sound manipulation and acoustic noise mitigation.

  3. Natural convection in tunnels at Yucca Mountain and impact on drift seepage

    SciTech Connect (OSTI)

    Halecky, N.; Birkholzer, J.T.; Peterson, P.

    2010-04-15

    The decay heat from radioactive waste that is to be disposed in the once proposed geologic repository at Yucca Mountain (YM) will significantly influence the moisture conditions in the fractured rock near emplacement tunnels (drifts). Additionally, large-scale convective cells will form in the open-air drifts and will serve as an important mechanism for the transport of vaporized pore water from the fractured rock in the drift center to the drift end. Such convective processes would also impact drift seepage, as evaporation could reduce the build up of liquid water at the tunnel wall. Characterizing and understanding these liquid water and vapor transport processes is critical for evaluating the performance of the repository, in terms of water-induced canister corrosion and subsequent radionuclide containment. To study such processes, we previously developed and applied an enhanced version of TOUGH2 that solves for natural convection in the drift. We then used the results from this previous study as a time-dependent boundary condition in a high-resolution seepage model, allowing for a computationally efficient means for simulating these processes. The results from the seepage model show that cases with strong natural convection effects are expected to improve the performance of the repository, since smaller relative humidity values, with reduced local seepage, form a more desirable waste package environment.

  4. Application Performance Variability on Hopper

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Application Performance Variability on Hopper Application Performance Variability on Hopper Introduction The Hopper system is a Cray XE6 system with roughly 6300 compute nodes. In normal day to day operations, Hopper can be running hundreds of individual applications at any given time. Some users have reported application runtime variability, in some cases as large as 30-40%. Non-uniform runtimes makes it more difficult for scientists to measure the performance of their codes and to estimate the

  5. Convection Heat Transfer in Three-Dimensional Turbulent Separated/Reattached Flow

    SciTech Connect (OSTI)

    Bassem F. Armaly

    2007-10-31

    The measurements and the simulation of convective heat transfer in separated flow have been a challenge to researchers for many years. Measurements have been limited to two-dimensional flow and simulations failed to predict accurately turbulent heat transfer in the separated and reattached flow region (prediction are higher than measurements by more than 50%). A coordinated experimental and numerical effort has been initiated under this grant for examining the momentum and thermal transport in three-dimensional separated and reattached flow in an effort to provide new measurements that can be used for benchmarking and for improving the simulation capabilities of 3-D convection in separated/reattached flow regime. High-resolution and non-invasive measurements techniques are developed and employed in this study to quantify the magnitude and the behavior of the three velocity components and the resulting convective heat transfer. In addition, simulation capabilities are developed and employed for improving the simulation of 3-D convective separated/reattached flow. Such basic measurements and simulation capabilities are needed for improving the design and performance evaluation of complex (3-D) heat exchanging equipment. Three-dimensional (3-D) convective air flow adjacent to backward-facing step in rectangular channel is selected for the experimental component of this study. This geometry is simple but it exhibits all the complexities that appear in any other separated/reattached flow, thus making the results generated in this study applicable to any other separated and reattached flow. Boundary conditions, inflow, outflow, and wall thermal treatment in this geometry can be well measured and controlled. The geometry can be constructed with optical access for non-intrusive measurements of the flow and thermal fields. A three-component laser Doppler velocimeter (LDV) is employed to measure simultaneously the three-velocity components and their turbulent fluctuations

  6. VariableR reclustering in multiple top quark events - Oral Presentatio...

    Office of Scientific and Technical Information (OSTI)

    VariableR reclustering in multiple top quark events - Oral Presentation Citation Details In-Document Search Title: VariableR reclustering in multiple top quark events - Oral...

  7. Sandia defines solar variability zones

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    defines solar variability zones - Sandia Energy Energy Search Icon Sandia Home Locations ... Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power ...

  8. NREL: Transmission Grid Integration - Variability of Renewable...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Variability of Renewable Energy Sources Wind and solar energy are referred to as variable generation sources because their ... at a single site is significantly less variable. ...

  9. Strontium isotope investigation of ungulate movement patterns on the Pleistocene Paleo-Agulhas Plain of the Greater Cape Floristic Region, South Africa

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Copeland, Sandi R.; Cawthra, Hayley C.; Fisher, Erich C.; Lee-Thorp, Julia A.; Cowling, Richard M.; le Roux, Petrus J.; Hodgkins, Jamie; Marean, Curtis W.

    2016-04-16

    Middle Stone Age sites located within the Greater Cape Floristic Region on the South African southern coast have material culture with early evidence for key modern human behaviors such as projectile weaponry, large animal hunting, and symbolic behavior. In order to interpret how and why these changes evolved, it is necessary to understand their ecological context as it has direct relevance to foraging behavior. During periods of lowered sea level, a largely flat and vast expanse of land existed south of the modern coastline, but it is now submerged by higher sea levels. This exposed area, the Paleo-Agulhas Plain, likelymore » created an ecological context unlike anything in the region today, as evidenced by fossil assemblages dominated by migratory ungulates. One hypothesis is that the Paleo-Agulhas Plain supported a migration ecosystem of large grazers driven by summer rainfall, producing palatable forage during summer in the east, and winter rainfall, producing palatable forage during winter in the west. Furthermore, ungulates may have been moving from the coastal plain in the south to the interior north of the Cape Fold Mountains, as observed for elephants in historic times.« less

  10. Two-phase convective CO2 dissolution in saline aquifers

    SciTech Connect (OSTI)

    Martinez, Mario J.; Hesse, Marc A.

    2016-01-01

    Geologic carbon storage in deep saline aquifers is a promising technology for reducing anthropogenic emissions into the atmosphere. Dissolution of injected CO2 into resident brines is one of the primary trapping mechanisms generally considered necessary to provide long-term storage security. Given that diffusion of CO2 in brine is woefully slow, convective dissolution, driven by a small increase in brine density with CO2 saturation, is considered to be the primary mechanism of dissolution trapping. Previous studies of convective dissolution have typically only considered the convective process in the single-phase region below the capillary transition zone and have either ignored the overlying two-phase region where dissolution actually takes place or replaced it with a virtual region with reduced or enhanced constant permeability. Our objective is to improve estimates of the long-term dissolution flux of CO2 into brine by including the capillary transition zone in two-phase model simulations. In the fully two-phase model, there is a capillary transition zone above the brine-saturated region over which the brine saturation decreases with increasing elevation. Our two-phase simulations show that the dissolution flux obtained by assuming a brine-saturated, single-phase porous region with a closed upper boundary is recovered in the limit of vanishing entry pressure and capillary transition zone. For typical finite entry pressures and capillary transition zone, however, convection currents penetrate into the two-phase region. As a result, this removes the mass transfer limitation of the diffusive boundary layer and enhances the convective dissolution flux of CO2 more than 3 times above the rate assuming single-phase conditions.