The retrieval of warm rain from CloudSat

An algorithm for the retrieval of warm rain over oceans for CloudSat that uses ancillary information from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument is presented. The method builds upon the architecture of the standard CloudSat 2C‐RAIN‐PROFILE product. Several general enhancements of that architecture have been made, including the implementation of a fast two‐stream multiple‐scattering radar model and a detailed error characterization. The algorithm has also been modified to specifically target the retrieval of warm rain by using ancillary MODIS visible optical depth observations to construct a parameterization of the cloud water path, implementing a model of the evaporation of rain below cloud base, and introducing a realistic representation of warm raindrop size distributions. With these important algorithm modifications, the CloudSat 2C‐RAIN‐PROFILE product is ideally suited to examine the distribution and magnitude of light rain over oceans.