Concepts for a geostationary microwave imaging sounder (GeoMIS)

The high frequencies (and short wavelengths) suited for atmospheric monitoring do not require a large aperture. An antenna of 3.5 meters diameter-comparable to communications antennas already in use-would give spatial resolution better than that from low-orbit microwave sensors, such as SSM/I and AMSU. The authors compare the expected capability of such a sensor with needs enunciated by Shenk et al. (1987), with emphasis on severe storms and tropical cyclones. The short-wavelength microwave spectrum enhances the optimization of spatial and temporal resolution over a compact part of the spectrum where profiles of temperature and moisture; as well as imagery of clouds and precipitation can all be obtained. Such a capability provides profiles under clouds; and precipitation mapping, as IR sensors do not. More than mere mapping of precipitation is possible, though minute-by-minute observation of storm structure, the presence of hail, and possible flooding are great improvements over occasional observations by low-Earth orbiters.