Stability of Shallow Cumulus Cloud Topped Boundary Layers Observed by A-Train Satellites and Comparison with Numerical Model Studies

Many theoretical and numerical model studies have shown that the persistence or break-up of the boundary layer low clouds is highly sensitive to the cloud top entrainment instability (CTEI) parameter. Although field campaign observations have been used to examine this hypothesis, they are quite limited in spatial and temporal coverage. Recently, it has been shown that the AIRS retrieval yield (percentage of high quality temperature and water vapor profiles to the surface) over the subtropical oceans within cloud-topped boundary layers is 61-71% globally, and 80-90% throughout the subtropical trade cumulus regions (Yue et al. 2011). Therefore unique, informative and representative observations can be obtained from satellites to study the vertical profiles of atmospheric boundary layer temperature and water vapor, and cloud top stability parameters. In this study, synergistic AIRS, and MODIS data have been used to explore the relationship between boundary layer thermodynamic parameters and shallow cumulus clouds. Results derived from satellite observations will be compared to radiosonde data collocated with satellite ground-tracks, and to numerical results from a simplified single column model.