Under the Professional Opportunities for Women in Research and Education (POWRE) Program, the Principal Investigator will investigate the dependence of the stratocumulus cloud layer radiative parameters on cloud inhomogeneity. Radiative properties of clouds is a factor very important to a variety of meteorological processes that range from local weather to climate issues. Current knowledge of these radiative characteristics, however, is somewhat lacking. The Principal InvestigatorÆs first task is to evaluate the accuracy of cloud optical depth parameterizations that are most commonly used in various applications and satellite retrievals. The evaluation will be based on simulations with an advanced research numerical model which includes explicit formulation of cloud microphysics. The observations from the Atlantic Stratocumulus Experiment, Southern Ocean Cloud Experiment, and Monterey Area Ship Track Experiment will provide the data for the initialization of the numerical model. The exact solution based on the known drop size distributions will be compared with parameterizations based on bulk parameters. It is expected that the study will result in a better understanding of the effect of cloud inhomogeneity on cloud radiative parameters and improvement of their formulation in large-scale models that cannot accommodate explicit treatment of cloud microphysics. The second task win be to investigate quantitatively how the bias introduced by the plane-parallel or independent pixel approximation depends on the statistical parameters describing the cloud microphysical inhomogeneity. The parameters characterizing the spatial inhomogeneity will be related to the bias introduced by plane-parallel and independent pixel approximations. The correction of the bias will increase the accuracy of the radiative transfer calculations in the stratocumulus boundary layer clouds. This research under the NSF POWRE Program will also help the Principal Investigator to gain new expertise in the state of the art numerical modeling and observations related to the radiative transfer problems.
