scholarly journals Geographically versus dynamically defined boundary layer cloud regimes and their use to evaluate general circulation model cloud parameterizations

2013 ◽  
Vol 40 (18) ◽  
pp. 4951-4956 ◽  
Author(s):  
Christine C.W. Nam ◽  
Johannes Quaas
Keyword(s):  
Boundary Layer ◽  
General Circulation Model ◽  
General Circulation ◽  
Circulation Model ◽  
Model Cloud ◽  
Boundary Layer Cloud ◽  
Cloud Regimes ◽  
Layer Cloud

scholarly journals Evaluation of boundary layer cloud parameterizations in the ECHAM5 general circulation model using CALIPSO and CloudSat satellite data

2014 ◽  
Vol 6 (2) ◽  
pp. 300-314 ◽  
Author(s):  
Christine C. W. Nam ◽  
Johannes Quaas ◽  
Roel Neggers ◽  
Colombe Siegenthaler-Le Drian ◽  
Francesco Isotta
Keyword(s):  
Boundary Layer ◽  
General Circulation Model ◽  
Satellite Data ◽  
General Circulation ◽  
Circulation Model ◽  
Boundary Layer Cloud ◽  
Layer Cloud

scholarly journals Marine boundary layer cloud regimes and POC formation in a CRM coupled to a bulk aerosol scheme

2013 ◽  
Vol 13 (24) ◽  
pp. 12549-12572 ◽  
Author(s):  
A. H. Berner ◽  
C. S. Bretherton ◽  
R. Wood ◽  
A. Muhlbauer
Keyword(s):  
Boundary Layer ◽  
Marine Boundary Layer ◽  
Three Dimensional ◽  
Two Dimensional ◽  
State Variables ◽  
Liquid Water Path ◽  
Modeling Framework ◽  
Boundary Layer Cloud ◽  
Cloud Regimes ◽  
Layer Cloud

Abstract. A cloud-resolving model (CRM) coupled to a new intermediate-complexity bulk aerosol scheme is used to study aerosol–boundary-layer–cloud–precipitation interactions and the development of pockets of open cells (POCs) in subtropical stratocumulus cloud layers. The aerosol scheme prognoses mass and number concentration of a single lognormal accumulation mode with surface and entrainment sources, evolving subject to processing of activated aerosol and scavenging of dry aerosol by clouds and rain. The CRM with the aerosol scheme is applied to a range of steadily forced cases idealized from a well-observed POC. The long-term system evolution is explored with extended two-dimensional (2-D) simulations of up to 20 days, mostly with diurnally averaged insolation and 24 km wide domains, and one 10 day three-dimensional (3-D) simulation. Both 2-D and 3-D simulations support the Baker–Charlson hypothesis of two distinct aerosol–cloud "regimes" (deep/high-aerosol/non-drizzling and shallow/low-aerosol/drizzling) that persist for days; transitions between these regimes, driven by either precipitation scavenging or aerosol entrainment from the free-troposphere (FT), occur on a timescale of ten hours. The system is analyzed using a two-dimensional phase plane with inversion height and boundary layer average aerosol concentrations as state variables; depending on the specified subsidence rate and availability of FT aerosol, these regimes are either stable equilibria or distinct legs of a slow limit cycle. The same steadily forced modeling framework is applied to the coupled development and evolution of a POC and the surrounding overcast boundary layer in a larger 192 km wide domain. An initial 50% aerosol reduction is applied to half of the model domain. This has little effect until the stratocumulus thickens enough to drizzle, at which time the low-aerosol portion transitions into open-cell convection, forming a POC. Reduced entrainment in the POC induces a negative feedback between the areal fraction covered by the POC and boundary layer depth changes. This stabilizes the system by controlling liquid water path and precipitation sinks of aerosol number in the overcast region, while also preventing boundary layer collapse within the POC, allowing the POC and overcast to coexist indefinitely in a quasi-steady equilibrium.

scholarly journals Antarctic boundary layer parametrization in a general circulation model: 1-D simulations facing summer observations at Dome C

2017 ◽  
Vol 122 (13) ◽  
pp. 6818-6843 ◽  
Author(s):  
Etienne Vignon ◽  
Frédéric Hourdin ◽  
Christophe Genthon ◽  
Hubert Gallée ◽  
Eric Bazile ◽  
...  
Keyword(s):  
Boundary Layer ◽  
General Circulation Model ◽  
General Circulation ◽  
Circulation Model ◽  
Antarctic Boundary Layer

Evaluation of tropical cloud regimes in observations and a general circulation model

2008 ◽  
Vol 32 (2-3) ◽  
pp. 355-369 ◽  
Author(s):  
Yonghua Chen ◽  
Anthony D. Del Genio
Keyword(s):  
General Circulation Model ◽  
General Circulation ◽  
Circulation Model ◽  
Cloud Regimes
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