Satellite-Derived Drizzle Rates in Boundary Layer Clouds Estimated from Co-Located Cloudsat and AMSR/E Retrievals.

A new product offers estimates of drizzle rates in boundary layer clouds using the 89GHz microwave brightness temperatures (Tb) from the AMSR/E sensor on board the Aqua satellite at a 5.4km resolution. This product is made using an algorithm that takes advantage of CloudSat Rain_Profile rain rate observations that coincide with AMSR/E Tb observations, allowing for a quantification of rain rate for each overlapping CloudSat and Tb measurement. Confounding variables that affect Tb such as column-integrated water vapor, sea surface temperature, 10-meter wind speed, and cloud ice content are accounted for. A variety of precipitation statistics are available including mean rain rates, rates when raining, and maximum rain rates for each Tb retrieval. Preliminary results show an unprecedented level of detail for satellite-derived precipitation estimates. Heavy drizzle is shown to coincide with cores within closed and especially open cells. Comparisons with the existing AMSR/E precipitation product shows that this new drizzle product senses over 90% of the precipitation seen by the existing product, while that product senses less than half of the precipitation seen by this new product.