Establishing closure of the global hydrologic cycle is a fundamental goal in advancing our understanding of the global climate system that requires accurate assessment of the regional and temporal distribution of precipitation. While significant progress has been made in satellite-based precipitation measurement, light precipitation is poorly sampled by current instruments but may represent a significant component of total precipitation particularly at latitudes poleward of 30 degrees. By virtue of its sensitivity, the CloudSat Cloud Profiling Radar (CPR) offers a unique opportunity to perform a global survey of light rainfall and quantify its contribution to the global water cycle. The proposed research will exploit CPR observations in conjunction with data from other A-Train sensors to (a) generate a global light rainfall dataset, (b) characterize statistically the spatial distribution of global light rainfall, (c) quantify the fraction of global light rainfall that is missed by current precipitation sensors, (d) assess the fidelity of current rainfall products in light of observing system limitations, (e) advance our understanding of the role of aerosols in modifying light rainfall in turbid air masses, and (f) examine drizzle regimes in pristine air masses and their relationship to the accompanying cloud top particle size. The products of this research will complete the rain rate histogram in a regime that current sensors have the most difficulty in identifying. Scientific outcomes from this effort will help improve our understanding of the importance of light precipitation regimes within the global hydrological cycle in the context of climate change and mankind�s role within it.
