Doppler Radar and Microwave Radiometer Derived Stratus Cloud Particle Size Distributions

Summary This paper demonstrates that number concentration and vertical profiles of liquid water content and effective radius can be retrieved using liquid water path estimates and vertical profiles of radar reflectivity factor and Doppler velocity. An important feature of the proposed retrieval is that the height dependence of the median radius, r ni , of the cloud particle size distribution is estimated from vertical Doppler velocity measurements obtained by a 35-GHz cloud radar. Although most of the variations in downward shortwave irradiances at the surface are caused by variations in the liquid water path, using retrieved cloud particle size distributions improve computation results from those using a climatological value. Acknowledgments We thank L. Smith and M. Ovtchinnikov for useful discussions and E. J. Mlawer for supplying the longwave k-distribution model. S. Kato was supported by the National Aeronautics and Space Administration (NASA) Clouds and the Earth’s Radiant Energy System grant (NAG-1-1963). E. Clothiaux received support for this research from the Environmental Science Division of the U.S. Department of Energy (under grant DE-FG0290ER61071).