GPM Microwave Imager

The GPM Microwave Imager is a conical-scanning passive microwave radiometer on the GPM Core Observatory. It uses 13 channels across 10.65, 18.7, 23.8, 36.5, 89, 166.5, and 183.31 GHz, with horizontal and vertical polarization coverage across the channel set ^{[1] [2] [3]}. In the GPM mission, GMI supports near-global precipitation retrieval, frequent revisit, precipitation standard products, and constellation radiometric-standard functions ^[1]. Its scan geometry uses a 1.2 m antenna, 32 rpm rotation, and a 52.8 degree Earth-incidence angle ^{[1] [2]}. The scan swath is 885 km by the instrument scan definition ^[1]. The useful-swath value is narrower at 850 km ^[2]. The GMI Core utilization period is 2014-2030 ^[2].