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Impacts of solar-absorbing aerosol layers on the transition of stratocumulus to trade cumulus clouds

Journal Article · · Atmospheric Chemistry and Physics (Online)
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Abstract. The effects of an initially overlying layer of solar-absorbing aerosol on the transition of stratocumulus to trade cumulus clouds are examined using large-eddy simulations. For lightly drizzling cloud the transition is generally hastened, resulting mainly from increased cloud droplet number concentration (Nc) induced by entrained aerosol. The increased Nc slows sedimentation of cloud droplets and shortens their relaxation time for diffusional growth, both of which accelerate entrainment of overlying air and thereby stratocumulus breakup. However, the decrease in albedo from cloud breakup is more than offset by redistributing cloud water over a greater number of droplets, such that the diurnal-average shortwave forcing at the top of the atmosphere is negative. The negative radiative forcing is enhanced by sizable longwave contributions, which result from the greater cloud breakup and a reduced boundary layer height associated with aerosol heating. A perturbation of moisture instead of aerosol aloft leads to a greater liquid water path and a more gradual transition. Adding absorbing aerosol to that atmosphere results in substantial reductions in liquid water path (LWP) and cloud cover that lead to positive shortwave and negative longwave forcings on average canceling each other. Only for heavily drizzling clouds is the breakup delayed, as inhibition of precipitation overcomes cloud water loss from enhanced entrainment. Considering these simulations as an imperfect proxy for biomass burning plumes influencing Namibian stratocumulus, we expect regional indirect plus semi-direct forcings to be substantially negative to negligible at the top of the atmosphere, with its magnitude sensitive to background and perturbation properties.

Research Organization:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE; USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Grant/Contract Number:
SC0012704; SC0013489
OSTI ID:
1459765
Alternate ID(s):
OSTI ID: 1413959
Report Number(s):
BNL--114819-2017-JA
Journal Information:
Atmospheric Chemistry and Physics (Online), Journal Name: Atmospheric Chemistry and Physics (Online) Journal Issue: 20 Vol. 17; ISSN 1680-7324
Publisher:
Copernicus Publications, EGUCopyright Statement
Country of Publication:
Germany
Language:
English

References (59)

RACORO continental boundary layer cloud investigations: 1. Case study development and ensemble large-scale forcings: RACORO CASE STUDIES journal June 2015
Stratocumulus to cumulus transition in the presence of elevated smoke layers: MARINE LOW CLOUD TRANSITION WITH SMOKE journal December 2015
The role of the southern African easterly jet in modifying the southeast Atlantic aerosol and cloud environments: Role of the AEJ-S over Southeast Atlantic journal April 2016
Pollution and the planetary albedo journal December 1974
Aerosols, clouds and radiation journal January 1991
Ship-produced cloud lines of 13 July 1991 journal November 1994
A parameterization of aerosol activation: 2. Multiple aerosol types journal March 2000
Can the direct and semi-direct aerosol effect compete with the indirect effect on a global scale? journal January 2001
Control of fossil-fuel particulate black carbon and organic matter, possibly the most effective method of slowing global warming journal January 2002
The mean physical and optical properties of regional haze dominated by biomass burning aerosol measured from the C-130 aircraft during SAFARI 2000: PHYSICAL-OPTICAL PROPERTIES OF BIOMASS AEROSOL journal February 2003
Comparison of aerosol size distributions, radiative properties, and optical depths determined by aircraft observations and Sun photometers during SAFARI 2000: SAFARI 2000 AEROSOL OPTICAL PROPERTIES journal February 2003
Solar radiative forcing by biomass burning aerosol particles during SAFARI 2000: A case study based on measured aerosol and cloud properties: FORCING BY BIOMASS AEROSOL DURING SAFARI journal February 2003
Soot and smoke aerosol may not warm climate: SOOT AND SMOKE AEROSOL MAY NOT WARM CLIMATE journal November 2003
On smoke suppression of clouds in Amazonia journal January 2005
Large-eddy simulations of the semidirect aerosol effect in shallow cumulus regimes: SEMIDIRECT AEROSOL EFFECT journal July 2005
Cloud droplet sedimentation, entrainment efficiency, and subtropical stratocumulus albedo journal January 2007
Injection height of biomass burning aerosols as seen from a spaceborne lidar journal January 2007
An observational study of the relationship between cloud, aerosol and meteorology in broken low-level cloud conditions journal January 2008
Direct and semidirect aerosol effects of southern African biomass burning aerosol journal January 2011
Radiative forcing and climate response journal March 1997
Direct observations of aerosol radiative forcing over the tropical Indian Ocean during the January-February 1996 pre-INDOEX cruise journal June 1998
Rapid calculation of radiative heating rates and photodissociation rates in inhomogeneous multiple scattering atmospheres journal January 1989
Large differences in tropical aerosol forcing at the top of the atmosphere and Earth's surface journal May 2000
Effect of precipitation on the albedo susceptibility of clouds in the marine boundary layer journal November 1994
The impact of humidity above stratiform clouds on indirect aerosol climate forcing journal December 2004
Satellite-derived direct radiative effect of aerosols dependent on cloud cover journal February 2009
Climate Effects of Black Carbon Aerosols in China and India journal September 2002
Aerosols, Cloud Microphysics, and Fractional Cloudiness journal September 1989
Dissipation of Marine Stratiform Clouds and Collapse of the Marine Boundary Layer Due to the Depletion of Cloud Condensation Nuclei by Clouds journal October 1993
Reduction of Tropical Cloudiness by Soot journal May 2000
Mid-Cretaceous (Albian–Santonian) sea surface temperature record of the tropical Atlantic Ocean journal January 2007
The Seasonal Cycle of Low Stratiform Clouds journal August 1993
A Model for Particle Microphysics, Turbulent Mixing, and Radiative Transfer in the Stratocumulus-Topped Marine Boundary Layer and Comparisons with Measurements journal April 1995
Moisture Transport, Lower-Tropospheric Stability, and Decoupling of Cloud-Topped Boundary Layers journal January 1997
Numerical Simulations and a Conceptual Model of the Stratocumulus to Trade Cumulus Transition journal January 1997
Large-Eddy Simulations of Strongly Precipitating, Shallow, Stratocumulus-Topped Boundary Layers journal December 1998
Limits to the Aerosol Indirect Radiative Effect Derived from Observations of Ship Tracks journal February 2002
Cloud Resolving Modeling of the ARM Summer 1997 IOP: Model Formulation, Results, Uncertainties, and Sensitivities journal February 2003
Outlook for Research on Subtropical Marine Stratification Clouds journal December 1984
Modeling Supersaturation and Subgrid-Scale Mixing with Two-Moment Bulk Warm Microphysics journal March 2008
Aerosol Effects on Clouds, Precipitation, and the Organization of Shallow Cumulus Convection journal February 2008
Aerosol Impacts on the Diurnal Cycle of Marine Stratocumulus journal August 2008
Large-Eddy Simulations of a Drizzling, Stratocumulus-Topped Marine Boundary Layer journal March 2009
On the Factors Modulating the Stratocumulus to Cumulus Transitions journal September 2011
Large-Eddy Simulations of EUCLIPSE–GASS Lagrangian Stratocumulus-to-Cumulus Transitions: Mean State, Turbulence, and Decoupling journal June 2016
Reduction of the Entrainment Velocity by Cloud Droplet Sedimentation in Stratocumulus journal March 2017
A New Double-Moment Microphysics Parameterization for Application in Cloud and Climate Models. Part I: Description journal June 2005
Cancellation of Aerosol Indirect Effects in Marine Stratocumulus through Cloud Thinning journal July 2007
Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign journal March 2015
The Convolution of Dynamics and Moisture with the Presence of Shortwave Absorbing Aerosols over the Southeast Atlantic journal March 2015
The semi-direct aerosol effect: Impact of absorbing aerosols on marine stratocumulus journal April 2004
Climate response to tropospheric absorbing aerosols in an intermediate general-circulation model: CLIMATE RESPONSE TO ABSORBING AEROSOLS journal January 2004
Stratocumulus cloud thickening beneath layers of absorbing smoke aerosol journal January 2010
On the transitions in marine boundary layer cloudiness journal January 2010
Parametric representation of the cloud droplet spectra for LES warm bulk microphysical schemes journal January 2010
Cloud condensation nuclei activity of fresh primary and aged biomass burning aerosol journal January 2012
Technical Note: Estimating aerosol effects on cloud radiative forcing journal January 2013
A single parameter representation of hygroscopic growth and cloud condensation nucleus activity journal January 2007
A global climatology of total columnar water vapour from SSM/I and MERIS journal January 2014

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