A Large Eddy Simulation Intercomparison Study of Shallow Cumulus Convection

Siebesma, A. Pier; Bretherton, Christopher S.; Brown, Andrew R.; Chlond, Andreas; Cuxart, Joan; Duynkerke, Peter G.; Jiang, Hongli; Khairoutdinov, Marat; Lewellen, D. C.; Moeng, Chin‐Hoh; Sánchez, Enrique; Stevens, Björn; Stevens, Dave

doi:10.1175/1520-0469(2003)60<1201:alesis>2.0.co;2

Cited by 660 publications

(896 citation statements)

References 59 publications

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“…The SAM (System for Atmospheric Modeling), nonhydrostatic, anelastic large eddy simulation (LES) model version 6.10.3 (Khairoutdinov and Randall, 2003) was used to simulate the well-studied trade cumulus case of the Barbados Oceanographic and Meteorological EXperiment (BOMEX; Holland and Rasmusson, 1973;Siebesma et al, 2003). The BOMEX case is an idealized trade cumulus cloud field that is based on observations made near Barbados during June 1969.…”

Section: Methodsmentioning

confidence: 99%

“…The BOMEX case is an idealized trade cumulus cloud field that is based on observations made near Barbados during June 1969. This case was initialized using the setup specified in Siebesma et al (2003). The setup includes surface fluxes and large-scale forcing (see details in Heiblum et al, 2016b).…”

Section: Methodsmentioning

confidence: 99%

“…2) and hence stronger mixing of the cloud with its environment (i.e. Small et al, 2009) and larger water loading due to rain suppression (Dagan et al, 2015a, Fig. 4a).…”

Section: Mean Cloud Field Properties Under Different Aerosol Loading mentioning

confidence: 99%

“…However, under subsaturation conditions, for the same reason, it implies higher evaporation efficiency. The evaporation induces downdrafts and stronger vorticity and hence can lead to stronger mixing of the cloud with its environment in polluted conditions Small et al, 2009). …”

Section: Introductionmentioning

confidence: 99%

“…For aerosol concentration values above the optimum, the suppressing aerosol effects take over, namely (1) stronger mixing of the cloud with its environment driven by the increased evaporation efficiency (Small et al, 2009) and (2) an increased water-loading effect due to the rain suppression.…”

Section: Introductionmentioning

confidence: 99%

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Time-dependent, non-monotonic response of warm convective cloud fields to changes in aerosol loading

et al. 2017

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Abstract. Large eddy simulations (LESs) with bin microphysics are used here to study cloud fields' sensitivity to changes in aerosol loading and the time evolution of this response. Similarly to the known response of a single cloud, we show that the mean field properties change in a nonmonotonic trend, with an optimum aerosol concentration for which the field reaches its maximal water mass or rain yield. This trend is a result of competition between processes that encourage cloud development versus those that suppress it. However, another layer of complexity is added when considering clouds' impact on the field's thermodynamic properties and how this is dependent on aerosol loading. Under polluted conditions, rain is suppressed and the non-precipitating clouds act to increase atmospheric instability. This results in warming of the lower part of the cloudy layer (in which there is net condensation) and cooling of the upper part (net evaporation). Evaporation at the upper part of the cloudy layer in the polluted simulations raises humidity at these levels and thus amplifies the development of the next generation of clouds (preconditioning effect). On the other hand, under clean conditions, the precipitating clouds drive net warming of the cloudy layer and net cooling of the sub-cloud layer due to rain evaporation. These two effects act to stabilize the atmospheric boundary layer with time (consumption of the instability). The evolution of the field's thermodynamic properties affects the cloud properties in return, as shown by the migration of the optimal aerosol concentration toward higher values.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…2) and hence stronger mixing of the cloud with its environment (i.e. Small et al, 2009) and larger water loading due to rain suppression (Dagan et al, 2015a, Fig. 4a).…”

Section: Mean Cloud Field Properties Under Different Aerosol Loading mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Time-dependent, non-monotonic response of warm convective cloud fields to changes in aerosol loading

et al. 2017

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Low cloud reduction in a greenhouse‐warmed climate: Results from Lagrangian LES of a subtropical marine cloudiness transition

Bretherton

Blossey

2014

J Adv Model Earth Syst

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Lagrangian large-eddy simulations of a composite stratocumulus to cumulus transition case over the subtropical northeast Pacific Ocean are subject to perturbed forcings that isolate the cloud response to CO 2 , to overall tropical warming, and to increased inversion stability over the subtropical subsidence regions. These simulations show that a tropical surface warming of 4 K induces substantial stratocumulus thinning via a thermodynamic mechanism: increased cloud layer humidity flux in a warmer climate induces an entrainment liquid-flux adjustment that dries the stratocumulus cloud layer, whether well mixed or cumulus coupled. A radiative mechanism amplifies this response: increased emissivity of the free troposphere due to increased CO 2 and water vapor reduces radiative driving of turbulence in a stratocumulus-capped boundary layer; a thinner stratocumulus layer accompanies less turbulence. In combination, a 4 K warming and CO 2 quadrupling greatly reduce low cloud and weaken the simulated shortwave cloud radiative effect by over 50%. Large increases in inversion stability in the stratocumulus regions could counter much of this cloudiness reduction.

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Configuration and assessment of the GISS ModelE2 contributions to the CMIP5 archive

Schmidt

Kelley

Nazarenko

et al. 2014

J Adv Model Earth Syst

630

469

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We present a description of the ModelE2 version of the Goddard Institute for Space Studies (GISS) General Circulation Model (GCM) and the configurations used in the simulations performed for the Coupled Model Intercomparison Project Phase 5 (CMIP5). We use six variations related to the treatment of the atmospheric composition, the calculation of aerosol indirect effects, and ocean model component. Specifically, we test the difference between atmospheric models that have noninteractive composition, where radiatively important aerosols and ozone are prescribed from precomputed decadal averages, and interactive versions where atmospheric chemistry and aerosols are calculated given decadally varying emissions. The impact of the first aerosol indirect effect on clouds is either specified using a simple tuning, or parameterized using a cloud microphysics scheme. We also use two dynamic ocean components: the Russell and HYbrid Coordinate Ocean Model (HYCOM) which differ significantly in their basic formulations and grid. Results are presented for the climatological means over the satellite era taken from transient simulations starting from the preindustrial (1850) driven by estimates of appropriate forcings over the 20th Century. Differences in base climate and variability related to the choice of ocean model are large, indicating an important structural uncertainty. The impact of interactive atmospheric composition on the climatology is relatively small except in regions such as the lower stratosphere, where ozone plays an important role, and the tropics, where aerosol changes affect the hydrological cycle and cloud cover. While key improvements over previous versions of the model are evident, these are not uniform across all metrics.

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A Large Eddy Simulation Intercomparison Study of Shallow Cumulus Convection

Cited by 660 publications

References 59 publications

Time-dependent, non-monotonic response of warm convective cloud fields to changes in aerosol loading

Time-dependent, non-monotonic response of warm convective cloud fields to changes in aerosol loading

Low cloud reduction in a greenhouse‐warmed climate: Results from Lagrangian LES of a subtropical marine cloudiness transition

Configuration and assessment of the GISS ModelE2 contributions to the CMIP5 archive

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