SIRAS-G, The Spaceborne Infrared Atmospheric Sounder: Infrared Imaging Spectroscopy from Geosynchronous Orbit

The Spaceborne Atmospheric Infrared Sounder for Geosynchronous Earth Orbit (SIRAS -G) represents a new approach to imaging spectrometry in the infrared suitable for Earth observation from geosynchronous orbit. SIRAS - G, one of nine proposals selected for development under NASA's 2002 Instrument Incubator Program, focuses on the development of an instrument concept that requires less mass and power than heritage geosynchronous sounding instruments while offering enhanced capabilities for the measurement of atmospheric temperature, water vapor profiles, and trace gas column abundances. The SIRAS -G flight instrument concept measures infrared radiation in 2048 spectral channels with a nominal spectral resolution ( ��/�) of 1100. Combined with large area 2 -D focal planes, this system simultaneously provides both high -resolution spectral and spatial imaging. In 1999, the SIRAS team built and tested the LWIR (12.0 - 15.4 ∝m) SIRAS spectrometer under NASA's Instrument Incubator Program (IIP -1999). SIRAS -G builds on this experience with a goal of producing and demonst rating a laboratory prototype instrument. In this paper, we describe planned development activities and potential future scientific instrument applications for this instrument concept.