Comparison of low-order and third-order turbulence closures in the cloud-resolving simulation of MC3E

 

Authors

Anning Cheng — IMSG
Kuan-Man Xu — NASA - Langley Research Center

Category

Field Campaigns

Description

An intermediately prognostic higher-order turbulence closure (IPHOC) scheme is implemented in the System for Atmospheric Modeling (SAM) cloud-resolving model (CRM) version 6.10 and is compared with a low-order turbulence closure (LOC) on their abilities to simulate data from the Midlatitude Continental Convective Clouds Experiment (MC3E). The SAM is run as a 3D CRM for 45 days to cover the whole MC3E period for all simulations. The horizontal domain size used in all experiments is 256 km, while the horizontal grid size is 4 km. The vertical grid-spacings are 50 m near surface and stretch to 1 km at the model top of 27 km. The results are reasonably well compared with available observations when the IPHOC scheme was used, while the resolved kinetic energy and circulations are overestimated when the LOC scheme was used. The subgrid-scale liquid water potential temperature and total water transports play an important role in the development of the clouds, especially for the boundary-layer clouds. The influence of the subgrid-scale parameterization on cold pool for the deep convective clouds is fairly noticeable.