Effect of Stratus on Solar Radiation: A Study Using Millimeter Wave Cloud Radar and Microwave Radiometer Data From the Southern Great Plains

Clouds are important players in the global radiation budget with low-level water clouds being one of the most influential types. Classified as stratocumulus and stratus, these water clouds cover 34% of oceans and 18% of land at any given time (Considine et al. 1997). A 50% plus global coverage, a high albedo when compared to the ocean, and temperatures comparable to the surface causes the low stratiform clouds to provide about 60% of the annually averaged net cloud radiative forcing (Hartmann et al. 1992). Therefore, variations in low cloud cover may have a significant impact on climate change. Additionally, changes in the microphyical properties of stratiform cloud quantified by the liquid water path (LWP) and size distribution may result in changes in albedo. This change in albedo, as a result of changes in microphysics, can impact climate change even if variations in cloud cover do not occur. Our goal is to study variations in the microphysical properties of stratus and their effect on solar radiation, thereby providing an assessment of the comparative importance of the various parameters, defining the warm cloud microphysics. We make use of data from the Southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) Cloud and Radiation Testbed (CART) site Central Facility (CF) as we require a statistically significant sample size for our study.