The D3R will operate as part of GPM Ground Validation, supporting GPM pre-launch algorithm development and will contribute to post-launch precipitation product validation. In the pre-launch era, the D3R provides independent estimation of hydrometeor classification and drop size distribution retrievals. The radar thus offers an insight into the microphysical processes that dominate the retrieval (and associated measurement error) of precipitation types and rates from satellite data.

An overview of the GPM mission and its goals, narrated by Sir Patrick Stewart.