Environmental sensitivities of shallow-cumulus dilution – Part 1: Selected thermodynamic conditions
Abstract
Cumulus entrainment, and its consequent dilution of buoyant cloud cores, strongly regulates the life cycle of shallow cumuli yet remains poorly understood. Herein, new insights into this problem are obtained through large-eddy simulations that systematically investigate the sensitivity of shallow-cumulus dilution to cloud-layer relative humidity (RH), cloud- and subcloud-layer depths, and continentality (i.e., the land–ocean contrast). The simulated cloud-core dilution is found to be strongly sensitive to continentality, with fractional dilution rates twice as large over the ocean as over land. Using a similarity theory based on the turbulent-kinetic-energy (TKE) budget, the reduced cloud-core dilution over land is attributed to larger cloud-base mass flux (mb), driven by stronger surface heating and subcloud turbulence. As mb increases, the fractional dilution rate must decrease to maintain energetic equilibrium. A positive sensitivity is also found to cloud-layer RH, with the core dilution increasing by 25 %–50 % for a 10 % enhancement in RH. This sensitivity is interpreted using the buoyancy-sorting hypothesis, in that mixtures of cloud and environmental air are more likely to become negatively buoyant and detrain (rather than diluting the cloud core) in drier cloud layers. By contrast, the sensitivities of (marine) shallow-cumulus dilution to cloud- and subcloud-layer depths aremore »
- Publication Date:
- Research Org.:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Atmospheric Radiation Measurement (ARM) Data Center
- Sponsoring Org.:
- USDOE Office of Science (SC), Biological and Environmental Research (BER); Natural Sciences and Engineering Research Council of Canada (NSERC)
- OSTI Identifier:
- 1725777
- Grant/Contract Number:
- SC0020083; SC0012704; NSERC/RGPIN 418372-17
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Atmospheric Chemistry and Physics (Online)
- Additional Journal Information:
- Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 20; Journal Issue: 21; Journal ID: ISSN 1680-7324
- Publisher:
- Copernicus Publications, EGU
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 54 ENVIRONMENTAL SCIENCES
Citation Formats
Drueke, Sonja, Kirshbaum, Daniel J., and Kollias, Pavlos. Environmental sensitivities of shallow-cumulus dilution – Part 1: Selected thermodynamic conditions. United States: N. p., 2020.
Web. doi:10.5194/acp-20-13217-2020.
Drueke, Sonja, Kirshbaum, Daniel J., & Kollias, Pavlos. Environmental sensitivities of shallow-cumulus dilution – Part 1: Selected thermodynamic conditions. United States. https://doi.org/10.5194/acp-20-13217-2020
Drueke, Sonja, Kirshbaum, Daniel J., and Kollias, Pavlos. Tue .
"Environmental sensitivities of shallow-cumulus dilution – Part 1: Selected thermodynamic conditions". United States. https://doi.org/10.5194/acp-20-13217-2020. https://www.osti.gov/servlets/purl/1725777.
@article{osti_1725777,
title = {Environmental sensitivities of shallow-cumulus dilution – Part 1: Selected thermodynamic conditions},
author = {Drueke, Sonja and Kirshbaum, Daniel J. and Kollias, Pavlos},
abstractNote = {Cumulus entrainment, and its consequent dilution of buoyant cloud cores, strongly regulates the life cycle of shallow cumuli yet remains poorly understood. Herein, new insights into this problem are obtained through large-eddy simulations that systematically investigate the sensitivity of shallow-cumulus dilution to cloud-layer relative humidity (RH), cloud- and subcloud-layer depths, and continentality (i.e., the land–ocean contrast). The simulated cloud-core dilution is found to be strongly sensitive to continentality, with fractional dilution rates twice as large over the ocean as over land. Using a similarity theory based on the turbulent-kinetic-energy (TKE) budget, the reduced cloud-core dilution over land is attributed to larger cloud-base mass flux (mb), driven by stronger surface heating and subcloud turbulence. As mb increases, the fractional dilution rate must decrease to maintain energetic equilibrium. A positive sensitivity is also found to cloud-layer RH, with the core dilution increasing by 25 %–50 % for a 10 % enhancement in RH. This sensitivity is interpreted using the buoyancy-sorting hypothesis, in that mixtures of cloud and environmental air are more likely to become negatively buoyant and detrain (rather than diluting the cloud core) in drier cloud layers. By contrast, the sensitivities of (marine) shallow-cumulus dilution to cloud- and subcloud-layer depths are weak, with a 3 % decrease for a doubling for the former and a 4 % reduction in dilution for a 50 % deeper subcloud layer. These surprisingly weak sensitivities are readily explained by offsetting effects in the TKE similarity theory. Altogether, these experimental findings provide useful, though still incomplete, guidance for flow-dependent shallow-cumulus entrainment formulations in large-scale models.},
doi = {10.5194/acp-20-13217-2020},
journal = {Atmospheric Chemistry and Physics (Online)},
number = 21,
volume = 20,
place = {United States},
year = {Tue Nov 10 00:00:00 EST 2020},
month = {Tue Nov 10 00:00:00 EST 2020}
}
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Works referenced in this record:
Entrainment processes in the diurnal cycle of deep convection over land
journal, December 2011
- Stirling, A. J.; Stratton, R. A.
- Quarterly Journal of the Royal Meteorological Society, Vol. 138, Issue 666
On the sensitivity of deep‐convection initiation to horizontal grid resolution
journal, January 2020
- Tang, S. L.; Kirshbaum, D. J.
- Quarterly Journal of the Royal Meteorological Society, Vol. 146, Issue 728
Mixing-length controls on high-resolution simulations of convective storms: Mixing-Length Controls on Convective Storms
journal, April 2014
- Hanley, Kirsty E.; Plant, Robert S.; Stein, Thorwald H. M.
- Quarterly Journal of the Royal Meteorological Society, Vol. 141, Issue 686
Interpolation of LES Cloud Surfaces for Use in Direct Calculations of Entrainment and Detrainment
journal, February 2011
- Dawe, Jordan T.; Austin, Philip H.
- Monthly Weather Review, Vol. 139, Issue 2
Observations of fair-weather cumuli over land: Dynamical factors controlling cloud size and cover: OBSERVATIONS OF CUMULI OVER LAND
journal, October 2015
- Lamer, Katia; Kollias, Pavlos
- Geophysical Research Letters, Vol. 42, Issue 20
Adaptive detrainment in a convective parametrization
journal, August 2011
- Derbyshire, S. H.; Maidens, A. V.; Milton, S. F.
- Quarterly Journal of the Royal Meteorological Society, Vol. 137, Issue 660
Nature versus Nurture in Shallow Convection
journal, May 2010
- Romps, David M.; Kuang, Zhiming
- Journal of the Atmospheric Sciences, Vol. 67, Issue 5
A Large Eddy Simulation Intercomparison Study of Shallow Cumulus Convection
journal, May 2003
- Siebesma, A. Pier; Bretherton, Christopher S.; Brown, Andrew
- Journal of the Atmospheric Sciences, Vol. 60, Issue 10
Dependence of entrainment in shallow cumulus convection on vertical velocity and distance to cloud edge: ENTRAINMENT DEPENDENCE
journal, April 2016
- Tian, Yang; Kuang, Zhiming
- Geophysical Research Letters, Vol. 43, Issue 8
A Simple Parameterization for Detrainment in Shallow Cumulus
journal, February 2008
- de Rooy, Wim C.; Siebesma, A. Pier
- Monthly Weather Review, Vol. 136, Issue 2
Can aerosol decrease cloud lifetime?
journal, January 2009
- Small, Jennifer D.; Chuang, Patrick Y.; Feingold, Graham
- Geophysical Research Letters, Vol. 36, Issue 16
The Influence of Land Surface Heterogeneities on Cloud Size Development
journal, October 2014
- Rieck, Malte; Hohenegger, Cathy; van Heerwaarden, Chiel C.
- Monthly Weather Review, Vol. 142, Issue 10
Entrainment versus Dilution in Tropical Deep Convection
journal, November 2017
- Hannah, Walter M.
- Journal of the Atmospheric Sciences, Vol. 74, Issue 11
Subsiding Shells around Shallow Cumulus Clouds
journal, March 2008
- Heus, Thijs; Jonker, Harm J. J.
- Journal of the Atmospheric Sciences, Vol. 65, Issue 3
Modeling aerosol effects on shallow cumulus convection under various meteorological conditions observed over the Indian Ocean and implications for development of mass-flux parameterizations for climate models
journal, January 2008
- Wang, Hailong; McFarquhar, Greg M.
- Journal of Geophysical Research, Vol. 113, Issue D20
An entraining jet model for cumulo-nimbus updraughts
journal, January 1962
- Squires, P.; Turner, J. S.
- Tellus, Vol. 14, Issue 4
The Role of Entrainment in the Diurnal Cycle of Continental Convection
journal, May 2010
- Del Genio, Anthony D.; Wu, Jingbo
- Journal of Climate, Vol. 23, Issue 10
Analyzing the Climate Sensitivity of the HadSM3 Climate Model Using Ensembles from Different but Related Experiments
journal, July 2009
- Rougier, Jonathan; Sexton, David M. H.; Murphy, James M.
- Journal of Climate, Vol. 22, Issue 13
Initiation of Deep Convection over an Idealized Mesoscale Convergence Line
journal, March 2017
- Rousseau-Rizzi, Raphaël; Kirshbaum, Daniel J.; Yau, Man Kong
- Journal of the Atmospheric Sciences, Vol. 74, Issue 3
Shallow Cumulus Convection
book, January 1998
- Siebesma, A. P.
- Buoyant Convection in Geophysical Flows
A similarity hypothesis for shallow-cumulus transports
journal, July 1999
- Grant, A. L. M.; Brown, A. R.
- Quarterly Journal of the Royal Meteorological Society, Vol. 125, Issue 558
Quantification of modelling uncertainties in a large ensemble of climate change simulations
journal, August 2004
- Murphy, James M.; Sexton, David M. H.; Barnett, David N.
- Nature, Vol. 430, Issue 7001
Moisture Vertical Structure, Column Water Vapor, and Tropical Deep Convection
journal, June 2009
- Holloway, Christopher E.; Neelin, J. David
- Journal of the Atmospheric Sciences, Vol. 66, Issue 6
Improving Parameterization of Entrainment Rate for Shallow Convection with Aircraft Measurements and Large-Eddy Simulation
journal, February 2016
- Lu, Chunsong; Liu, Yangang; Zhang, Guang J.
- Journal of the Atmospheric Sciences, Vol. 73, Issue 2
Racoro Extended-Term Aircraft Observations of Boundary Layer Clouds
journal, June 2012
- Vogelmann, Andrew M.; McFarquhar, Greg M.; Ogren, John A.
- Bulletin of the American Meteorological Society, Vol. 93, Issue 6
Precipitating convection in cold air: Virtual potential temperature structure
journal, January 2007
- Grant, A. L. M.
- Quarterly Journal of the Royal Meteorological Society, Vol. 133, Issue 622
Entrainment, Mixing, and Microphysics in Trade-Wind Cumulus
journal, January 2008
- E. Gerber, Hermann; M. Frick, Glendon; B. Jensen, Jorgen
- Journal of the Meteorological Society of Japan, Vol. 86A
High-Resolution Simulation of Shallow-to-Deep Convection Transition over Land
journal, December 2006
- Khairoutdinov, Marat; Randall, David
- Journal of the Atmospheric Sciences, Vol. 63, Issue 12
Shallow cumulus convection: A validation of large-eddy simulation against aircraft and Landsat observations
journal, July 2003
- Neggers, R. A. J.; Duynkerke, P. G.; Rodts, S. M. A.
- Quarterly Journal of the Royal Meteorological Society, Vol. 129, Issue 593
Large-eddy simulation of the diurnal cycle of shallow cumulus convection over land
journal, April 2002
- Brown, A. R.; Cederwall, R. T.; Chlond, A.
- Quarterly Journal of the Royal Meteorological Society, Vol. 128, Issue 582
Empirical relationship between entrainment rate and microphysics in cumulus clouds: ENTRAINMENT RATE AND MICROPHYSICS
journal, May 2013
- Lu, Chunsong; Niu, Shengjie; Liu, Yangang
- Geophysical Research Letters, Vol. 40, Issue 10
Controls on precipitation and cloudiness in simulations of trade-wind cumulus as observed during RICO: CONTROLS ON PRECIPITATION … IN TRADE-WIND CUMULUS
journal, February 2011
- vanZanten, Margreet C.; Stevens, Bjorn; Nuijens, Louise
- Journal of Advances in Modeling Earth Systems, Vol. 3, Issue 2
Estimation of entrainment rate in simple models of convective clouds
journal, January 2001
- Gregory, David
- Quarterly Journal of the Royal Meteorological Society, Vol. 127, Issue 571
Sensitivity of moist convection to environmental humidity
journal, October 2004
- Derbyshire, S. H.; Beau, I.; Bechtold, P.
- Quarterly Journal of the Royal Meteorological Society, Vol. 130, Issue 604
Association of parameter, software, and hardware variation with large-scale behavior across 57,000 climate models
journal, July 2007
- Knight, C. G.; Knight, S. H. E.; Massey, N.
- Proceedings of the National Academy of Sciences, Vol. 104, Issue 30
Large-Eddy Simulation and Parametrization of the Effects of Shear on Shallow Cumulus Convection
journal, April 1999
- Brown, A. R.
- Boundary-Layer Meteorology, Vol. 91, Issue 1
Shallow Cumulus Mixing and Subcloud-Layer Responses to Variations in Aerosol Loading
journal, July 2014
- Seigel, Robert B.
- Journal of the Atmospheric Sciences, Vol. 71, Issue 7
The impact of parametrized convection on cloud feedback
journal, November 2015
- Webb, Mark J.; Lock, Adrian P.; Bretherton, Christopher S.
- Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 373, Issue 2054
The turbulent kinetic energy budget for shallow cumulus convection
journal, January 2004
- Grant, A. L. M.; Lock, A. P.
- Quarterly Journal of the Royal Meteorological Society, Vol. 130, Issue 597
Invigoration of cumulus cloud fields by mesoscale ascent: Invigoration of Cumulus Cloud Fields
journal, May 2012
- Kirshbaum, D. J.; Grant, A. L. M.
- Quarterly Journal of the Royal Meteorological Society, Vol. 138, Issue 669
A Direct Measure of Entrainment
journal, June 2010
- Romps, David M.
- Journal of the Atmospheric Sciences, Vol. 67, Issue 6
Entrainment and detrainment in cumulus convection: an overview
journal, June 2012
- de Rooy, Wim C.; Bechtold, Peter; Fröhlich, Kristina
- Quarterly Journal of the Royal Meteorological Society, Vol. 139, Issue 670
Statistical analysis of an LES shallow cumulus cloud ensemble using a cloud tracking algorithm
journal, January 2012
- Dawe, J. T.; Austin, P. H.
- Atmospheric Chemistry and Physics, Vol. 12, Issue 2
On Constraining Estimates of Climate Sensitivity with Present-Day Observations through Model Weighting
journal, December 2011
- Klocke, Daniel; Pincus, Robert; Quaas, Johannes
- Journal of Climate, Vol. 24, Issue 23
Towards constraining climate sensitivity by linear analysis of feedback patterns in thousands of perturbed-physics GCM simulations
journal, July 2007
- Sanderson, Benjamin M.; Piani, C.; Ingram, W. J.
- Climate Dynamics, Vol. 30, Issue 2-3
Power-Law Scaling in the Internal Variability of Cumulus Cloud Size Distributions due to Subsampling and Spatial Organization
journal, May 2019
- Neggers, R. A. J.; Griewank, P. J.; Heus, T.
- Journal of the Atmospheric Sciences, Vol. 76, Issue 6
Representing the Sensitivity of Convective Cloud Systems to Tropospheric Humidity in General Circulation Models
journal, September 2011
- Del Genio, Anthony D.
- Surveys in Geophysics, Vol. 33, Issue 3-4
Aerosol effects on the lifetime of shallow cumulus
journal, January 2006
- Jiang, Hongli; Xue, Huiwen; Teller, Amit
- Geophysical Research Letters, Vol. 33, Issue 14
Rain in Shallow Cumulus Over the Ocean: The RICO Campaign
journal, December 2007
- Rauber, Robert M.; Stevens, Bjorn; Ochs, Harry T.
- Bulletin of the American Meteorological Society, Vol. 88, Issue 12
Estimation of convective entrainment properties from a cloud-resolving model simulation during TWP-ICE
journal, December 2015
- Zhang, Guang J.; Wu, Xiaoqing; Zeng, Xiping
- Climate Dynamics, Vol. 47, Issue 7-8
RACORO continental boundary layer cloud investigations: 2. Large-eddy simulations of cumulus clouds and evaluation with in situ and ground-based observations: LES OF RACORO BOUNDARY LAYER CUMULI
journal, June 2015
- Endo, Satoshi; Fridlind, Ann M.; Lin, Wuyin
- Journal of Geophysical Research: Atmospheres, Vol. 120, Issue 12
Advances in simulating atmospheric variability with the ECMWF model: From synoptic to decadal time-scales
journal, July 2008
- Bechtold, Peter; Köhler, Martin; Jung, Thomas
- Quarterly Journal of the Royal Meteorological Society, Vol. 134, Issue 634
Parametric Interpretation of Trade-Wind Cumulus Budget Studies
journal, October 1975
- Betts, Alan K.
- Journal of the Atmospheric Sciences, Vol. 32, Issue 10
Variability of Midtropospheric Moisture and Its Effect on Cloud-Top Height Distribution during TOGA COARE*
journal, December 1997
- Brown, Randy G.; Zhang, Chidong
- Journal of the Atmospheric Sciences, Vol. 54, Issue 23
A Benchmark Simulation for Moist Nonhydrostatic Numerical Models
journal, December 2002
- Bryan, George H.; Fritsch, J. Michael
- Monthly Weather Review, Vol. 130, Issue 12
Measurements of the Atmospheric Mass, Energy, and Momentum Budgets Over a 500-Kilometer Square of Tropical Ocean
journal, January 1973
- Holland, Joshua Z.; Rasmusson, Eugene M.
- Monthly Weather Review, Vol. 101, Issue 1
A Theory of Entrainment in Convective Currents
journal, April 1951
- Houghton, Henry G.; Cramer, Harrison E.
- Journal of Meteorology, Vol. 8, Issue 2
Some Bulk Properties of Cumulus Ensembles Simulated by a Cloud-Resolving Model. Part II: Entrainment Profiles
journal, November 1999
- Lin, Chichung
- Journal of the Atmospheric Sciences, Vol. 56, Issue 21
Size Statistics of Cumulus Cloud Populations in Large-Eddy Simulations
journal, April 2003
- Neggers, R. A. J.; Jonker, H. J. J.; Siebesma, A. P.
- Journal of the Atmospheric Sciences, Vol. 60, Issue 8
Low Cloud Type over the Ocean from Surface Observations. Part II: Geographical and Seasonal Variations
journal, March 1998
- Norris, Joel R.
- Journal of Climate, Vol. 11, Issue 3
Characteristics of Cumulus Band Clouds off the Coast of Hawaii
journal, February 1990
- Raga, Graciela B.; Jensen, Jørgen B.; Baker, Marcia B.
- Journal of the Atmospheric Sciences, Vol. 47, Issue 3
A Stochastic Mixing Model for Nonprecipitating Cumulus Clouds
journal, November 1986
- Raymond, David J.; Blyth, Alan M.
- Journal of the Atmospheric Sciences, Vol. 43, Issue 22
Convective Precursors and Predictability in the Tropical Western Pacific
journal, December 1999
- Sherwood, Steven C.
- Monthly Weather Review, Vol. 127, Issue 12
Evaluation of Parametric Assumptions for Shallow Cumulus Convection
journal, March 1995
- Siebesma, A. P.; Cuijpers, J. W. M.
- Journal of the Atmospheric Sciences, Vol. 52, Issue 6
Simulations of Trade Wind Cumuli under a Strong Inversion
journal, July 2001
- Stevens, Bjorn; Ackerman, Andrew S.; Albrecht, Bruce A.
- Journal of the Atmospheric Sciences, Vol. 58, Issue 14
ENTRAINMENT OF AIR INTO A CUMULUS CLOUD: (Paper presented 27 December 1946 at the Annual Meeting, A.M.S., Cambridge, Massachusetts)
journal, June 1947
- Stommel, Henry
- Journal of Meteorology, Vol. 4, Issue 3
Parameterization of the Bulk Effects of Lateral and Cloud-Top Entrainment in Transient Shallow Cumulus Clouds
journal, April 2002
- von Salzen, Knut; McFarlane, Norman A.
- Journal of the Atmospheric Sciences, Vol. 59, Issue 8
An Extended Eddy‐Diffusivity Mass‐Flux Scheme for Unified Representation of Subgrid‐Scale Turbulence and Convection
journal, March 2018
- Tan, Zhihong; Kaul, Colleen M.; Pressel, Kyle G.
- Journal of Advances in Modeling Earth Systems, Vol. 10, Issue 3
Large-eddy simulations of the diurnal cycle of shallow convection and cloudiness over the tropical Indian Ocean
journal, January 2008
- Wang, Hailong; McFarquhar, Greg M.
- Quarterly Journal of the Royal Meteorological Society, Vol. 134, Issue 632
Representing the Sensitivity of Convective Cloud Systems to Tropospheric Humidity in General Circulation Models
journal, September 2011
- Del Genio, Anthony D.
- Surveys in Geophysics, Vol. 33, Issue 3-4
Large-eddy simulation of the diurnal cycle of shallow cumulus convection over land
journal, April 2002
- Brown, A. R.; Cederwall, R. T.; Chlond, A.
- Quarterly Journal of the Royal Meteorological Society, Vol. 128, Issue 582