6533b85afe1ef96bd12b986d
RESEARCH PRODUCT
Explicit cloud-top entrainment parameterization in the global climate model ECHAM5-HAM
Peter SpichtingerUlrike LohmannC. Siegenthaler-le Driansubject
Physics::Fluid DynamicsConvectionBuoyancyScale (ratio)Cloud topTurbulence kinetic energyRadiative transferengineeringEnvironmental scienceLiquid water pathEntrainment (meteorology)engineering.materialAtmospheric sciencesdescription
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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2011-01-20 |