CloudSat observations of light precipitation

Establishing closure of the global hydrologic cycle, a fundamental goal in advancing our understanding of the global climate system, requires accurate assessment of the regional and temporal distribution of precipitation. While significant progress has been made in satellite-based precipitation measurement, light liquid precipitation and falling snow are poorly sampled by current instruments but may represent a significant component of total precipitation particularly at latitudes poleward of 40 degrees. By virtue of its sensitivity the CloudSat Cloud Profiling Radar (CPR), the first millimeter wavelength cloud radar to be flown in space, offers a unique opportunity to perform a global survey of light rainfall and snowfall and quantify their contribution to the global water cycle. This presentation will describe experimental precipitation algorithms for retrieving light liquid rainfall and falling snow from CPR reflectivity observations coupled with ancillary information from sensors aboard the Aqua satellite. The theoretical bases of these algorithms will be described and an overview of their implementation within the Naval Research Laboratory (NRL) NexSat satellite data processing system will be provided including details concerning the associated web-based interface for viewing images and requesting the products. Subject to their availability at the time of presentation, examples from CloudSat's first few orbits will be presented providing a first look at its detection capabilities and light precipitation products. Alternatively, similar results derived using airborne cloud radar data from recent field experiments will be provided.