Explicit cloud-top entrainment parameterization in the global climate model ECHAM5-HAM


Date

2011

Publication Type

Journal Article

ETH Bibliography

yes

Citations

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Data

Abstract

New developments in the turbulence parameterization in the general circulation model ECHAM5-HAM are presented. They consist mainly of an explicit entrainment closure at the top of stratocumulus-capped boundary layers and the addition of an explicit contribution of the radiative divergence in the buoyancy production term. The impact of the new implementations on a single column model study and on the global scale is presented here. The parameterization has a "smoothing" effect: the abnormally high values of turbulence kinetic energy are reduced, both in the single column and in the Californian stratocumulus region. A sensitivity study with prescribed droplet concentration shows a reduction in the sensitivity of liquid water path to increasing cloud aerosol optical depth. We also study the effect of the new implementation on a Pacific cross-section. The entrainment parameterization leads to an enhanced triggering of the convective activity.

Publication status

published

Editor

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Volume

11 (1)

Pages / Article No.

1971 - 2023

Publisher

Copernicus

Event

Edition / version

Methods

Software

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Date collected

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Organisational unit

03690 - Lohmann, Ulrike / Lohmann, Ulrike check_circle

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