All-Weather tropospheric 3D wind from microwave sounders

In its 2007 'Decadal Survey' (DS) of earth science missions for NASA [1] the U.S. National Research Council (NRC) recommended that a Doppler wind lidar be developed for a three-dimensional tropospheric winds mission ('3D-Winds'). It is expected that the next DS, currently under way, will put additional emphasis on the still pressing need for wind measurements from space. The first DS also called for a geostationary microwave sounder (GMS) on a Precipitation and All-weather Temperature and Humidity (PATH) mission. Such a sounder, the Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR), has been developed at the Jet Propulsion Laboratory (JPL). The PATH mission has not yet been funded by NASA, but a low-cost subset of PATH, GeoStorm was proposed as a hosted payload on a commercial communications satellite. Both PATH and GeoStorm will obtain frequent (every 15 minutes of better) measurements of tropospheric water vapor profiles, and they can be used to derive atmospheric motion vector (AMV) wind profiles even in the presence of clouds. We report on simulation studies of such wind vectors derived from a GMS or possibly from a cluster of low-earth-orbiting (LEO) small satellites (e.g., CubeSats).