GeoSTAR – The geosynchronous hurricane observatory

The Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) is a microwave sounder under development at NASA's Jet Propulsion Laboratory (JPL) that has capabilities similar to the Advanced Microwave Sounding Unit (AMSU) sounders currently operating on NASA, NOAA and ESA low-earth-orbiting satellites – i.e. similar spatial resolution, radiometric sensitivity and spectral coverage. Microwave sounders, such as AMSU and GeoSTAR, measure the 3-dimensional structure of temperature, water vapor, cloud liquid water, precipitation and other derived parameters under a wide range of weather conditions, including full cloud cover. With a recently developed method (described in a separate paper) it is also possible to measure the vertical structure of convection and precipitation when heavy convection prevents the retrieval of the standard parameters. GeoSTAR will provide these capabilities from geostationary orbit, with continuous synoptic monitoring of large portions of the visible hemisphere and a refresh cycle of 15-20 minutes. These capabilities make a geostationary sounder especially valuable as a hurricane and severe-storm observatory, and it is expected to have a significant impact in numerical weather prediction. There is a strong possibility that GeoSTAR can be implemented as a hosted payload in the near term, coincident with the next generation of NOAA geostationary weather satellites, the GOES-R series. The breakthrough enabling aperture synthesis concept that GeoSTAR is based on has been developed and demonstrated at JPL, largely through the NASA Instrument Incubator Program, and all key technology elements will be in place when the current IIP project is completed in 2011. A GeoSTAR space mission can then be initiated, and a low-cost joint NASA-NOAA Mission of Opportunity is a strong possibility, with a launch possible in the 2015-17 time frame. We discuss the status of the GeoSTAR development, possible mission scenarios and some of the science applications, which include real-time hurricane diagnostics and forecasts.

Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.