Improvement and Implementation of a Parameterization for Shallow Cumulus in the Global Climate Model ECHAM5-HAMSource: Journal of the Atmospheric Sciences:;2011:;Volume( 068 ):;issue: 003::page 515DOI: 10.1175/2010JAS3447.1Publisher: American Meteorological Society
Abstract: A transient shallow-convection scheme is implemented into the general circulation model ECHAM5 and the coupled aerosol model HAM, developed at the Max Planck Institute for Meteorology in Hamburg. The shallow-convection scheme is extended to take the ice phase into account. In addition, a detailed double-moment microphysics approach has been added. In this approach, the freezing processes and precipitation formation are dependent on aerosols. Furthermore, in the scheme, tracers are transported and scavenged consistently as in the rest of the model. Results of a single-column model simulation for the Barbados Oceanography and Meteorology Experiment (BOMEX) campaign are compared with previously published large-eddy simulation (LES) results. Compared to the standard version, the global ECHAM5-HAM simulations with the newly implemented scheme show a decreased frequency of shallow convection in better agreement with LES. Less shallow convection is compensated by more stratus and stratocumulus. Deep and especially midlevel convection are markedly affected by those changes, which in turn influence high-level clouds. Generally, a better agreement with the observations can be obtained. For a better understanding of the scheme?s impact and to test different setting parameters, sensitivity analyses are performed. The mixing properties, cloud-base vertical velocity, and launching layer of the test parcel, respectively, are varied. In this context, results from simulations without shallow convection are also presented.
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contributor author | Isotta, Francesco A. | |
contributor author | Spichtinger, P. | |
contributor author | Lohmann, U. | |
contributor author | von Salzen, K. | |
date accessioned | 2017-06-09T16:34:29Z | |
date available | 2017-06-09T16:34:29Z | |
date copyright | 2011/03/01 | |
date issued | 2011 | |
identifier issn | 0022-4928 | |
identifier other | ams-70249.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4212009 | |
description abstract | A transient shallow-convection scheme is implemented into the general circulation model ECHAM5 and the coupled aerosol model HAM, developed at the Max Planck Institute for Meteorology in Hamburg. The shallow-convection scheme is extended to take the ice phase into account. In addition, a detailed double-moment microphysics approach has been added. In this approach, the freezing processes and precipitation formation are dependent on aerosols. Furthermore, in the scheme, tracers are transported and scavenged consistently as in the rest of the model. Results of a single-column model simulation for the Barbados Oceanography and Meteorology Experiment (BOMEX) campaign are compared with previously published large-eddy simulation (LES) results. Compared to the standard version, the global ECHAM5-HAM simulations with the newly implemented scheme show a decreased frequency of shallow convection in better agreement with LES. Less shallow convection is compensated by more stratus and stratocumulus. Deep and especially midlevel convection are markedly affected by those changes, which in turn influence high-level clouds. Generally, a better agreement with the observations can be obtained. For a better understanding of the scheme?s impact and to test different setting parameters, sensitivity analyses are performed. The mixing properties, cloud-base vertical velocity, and launching layer of the test parcel, respectively, are varied. In this context, results from simulations without shallow convection are also presented. | |
publisher | American Meteorological Society | |
title | Improvement and Implementation of a Parameterization for Shallow Cumulus in the Global Climate Model ECHAM5-HAM | |
type | Journal Paper | |
journal volume | 68 | |
journal issue | 3 | |
journal title | Journal of the Atmospheric Sciences | |
identifier doi | 10.1175/2010JAS3447.1 | |
journal fristpage | 515 | |
journal lastpage | 532 | |
tree | Journal of the Atmospheric Sciences:;2011:;Volume( 068 ):;issue: 003 | |
contenttype | Fulltext |