A COMPAcr RADAR ALTIMETER SATELUTE FOR MONITORING GLOBAL CUMATE CHANGE

Altimetry has become the focus of global climate studies because it is the only tool available able to provide both mesoscale (100-500 kIn) and basin-scale (10,000 kIn) circulation information on a global, synoptic basis. . The Atlas-launched Navy Geosat mission proved the capability of the radar altimeter to measure the mesoscale ocean features. A lightsat compatible Geosat Follow-On Technology Model (GTM) altimeter, capable of Scout or Pegasus launch and with half the weight and power (63-lbs and 69-W) of the Geosat altimeter, was developed and built at JHU/AP1... This altimeter demonstrated the feasibility of a compact satellite version of Geosat. The Navy is now procuring a series of compact altimeter satellites to support their tactical operations and to provide mesoscale data for global climate change monitoring. With the successful performance evaluation of GTM, APL now is pursuing the next step in exploring a compact altimeter mission to meet the needs of basin-scale global climate monitoring. A conceptual design, showing that the stringent centimeter precision measurement capability requirement can be met, includes a C-band channel for correcting for ionospheric effects. This improvement in performance will provide a basin-scale measurement capability in a compact satellite design that is a fraction of the weight and power of the Arianelaunched· TOPEX mission.