The GSMaP Precipitation Retrieval Algorithm for Microwave Sounders-Part I: Over-Ocean Algorithm

• Published in: IEEE transactions on geoscience and remote sensing 2009-09, Vol.47 (9), p.3084-3097
• Main Authors: Shige, S., Yamamoto, T., Tsukiyama, T., Kida, S., Ashiwake, H., Kubota, T., Seto, S., Aonashi, K., Okamoto, K.
• Format: Article
• Language: English
• Subjects: Acoustic scattering; Aerospace engineering; Algorithms; Applied geophysics; Earth; Earth sciences; Earth, ocean, space; Estimates; Exact sciences and technology; Extraterrestrial measurements; Internal geophysics; Marine; Meteorology; Microwave radiometer (MWR); Microwave radiometry; Microwave sensors; microwave sounder; NOAA; Precipitation; Rain; rain-rate retrieval; Rainfall; Retrieval; Satellite broadcasting; Sea measurements; Winter
• ISSN: 0196-2892; 1558-0644
• DOI: 10.1109/TGRS.2009.2019954

We develop an over-ocean rainfall retrieval algorithm for the Advanced Microwave Sounding Unit (AMSU) based on the Global Satellite Mapping of Precipitation (GSMaP) microwave radiometer algorithm. This algorithm combines an emission-based estimate from brightness temperature (Tb) at 23 GHz and a scattering-based estimate from Tb at 89 GHz, depending on a scattering index (SI) computed from Tb at both 89 and 150 GHz. Precipitation inhomogeneities are also taken into account. The GSMaP-retrieved rainfall from the AMSU (GSMaP_AMSU) is compared with the National Oceanic and Atmospheric Administration (NOAA) standard algorithm (NOAA_AMSU)-retrieved data using Tropical Rainfall Measuring Mission (TRMM) data as a reference. Rain rates retrieved by GSMaP_AMSU have better agreement with TRMM estimates over midlatitudes during winter. Better estimates over multitudes over winter are given by the use of Tb at 23 GHz in the GSMaP_AMSU algorithm. It was also shown that GSMaP_AMSU has higher rain detection than NOAA_AMSU.