Improving the representation of marine boundary-layer clouds and drizzle in CAM based on ARM observations in the Azores

Description

Model deficiencies in the cloud-drizzle-turbulence interactions in CAM with Cloud Layers Unified by Binormals (CLUBB) scheme and the updated cloud and precipitation microphysics (MG2) scheme have been found in a model assessment study based on ARM observations. To address the identified precipitation parameterization deficiencies, this study will present the latest process-oriented evaluation on the precipitation properties in CAM based on ARM observations in the Azores. Specifically, we will evaluate the simulated vertical profiles of cloud and precipitation water with CLUBB and MG2, and improve the precipitation fraction parameterization in MG2. Furthermore, we will demonstrate the impact of the updated precipitation parameterization on the representation of marine boundary-layer clouds by comparing the updated simulations with observations. Acknowledgement: This work is supported by the ASR Program for the Office of Science of the U.S. DOE. This work was performed under the auspices of the U.S. DOE by LLNL under contract DE-AC52-07NA27344. LLNL-ABS-716523.