On the Summertime Shallow Cumulus Clouds at Southern Great Plains

Yunyan Zhang Lawrence Livermore National Laboratory
Stephen Klein Lawrence Livermore National Laboratory
Pavlos Kollias Stony Brook University
Arunchandra Chandra McGill University

Category: Modeling

Working Group: Cloud Life Cycle

Shallow cumulus clouds are important for surface radiation budget and vertical moisture transport. They occur very often during summertime over large areas near Southern Great Plains (SGP). This study aims to gain more insights on shallow cumulus cloud dynamics and life cycle with the help of both the modeling tools, such as large-eddy simulations (LES), and the ARM observations, especially the newly developed retrieval data of vertical velocity of air motions inside and beneath shallow cumulus clouds (Kollias et al. 2001, Kollias et al. 2003, Chandra et al., 2009). Based on long-term observations at the ARM SGP site, we develop composite cases of typical shallow cumulus clouds, which are closely related to surface heat fluxes and atmospheric boundary layer development. To develop composites, we investigate the ARM observations on cloud macrophysics, such as cloud base, fraction, thickness, and diurnal variation, and the associated meteorological conditions. These composite cases will help to generate statistics for cloud dynamics, such as mass flux, an important variable for cloud and convection parameterizations in large-scale models. These composite cases will further serve as testbeds for LES and single-column models to validate and explain observations and to test and improve parameterizations in large-scale models.

This poster will be displayed at ASR Science Team Meeting.