Diagnosing causes of cloud parameterization deficiencies using ARM measurements over the SGP site

Description

Decade-long continuous surface-based measurements at Southern Great Plains (SGP) collected by the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Climate Research Facility are first used to evaluate the three major reanalyses (i.e., ERA-Interim, NCEP/NCAR Reanalysis I, and NCEP/DOE Reanalysis II) to identify model biases in simulating surface shortwave cloud forcing and total cloud fraction. The results show large systematic lower biases in the modeled surface shortwave cloud forcing and cloud fraction from all three reanalysis data sets. Then we focus on diagnosing the causes of these model biases using the Active Remote Sensing of Clouds (ARSCL) products (e.g., vertical distribution of cloud fraction, cloud-base and cloud-top heights, and cloud optical depth) and meteorological measurements (temperature, humidity, and stability). Efforts are made to couple cloud properties with boundary processes in the diagnosis.