IMPROVED STRATOSPHERIC AND MESOSPHERIC SOUNDER VALIDATION - GENERAL-APPROACH AND IN-FLIGHT RADIOMETRIC CALIBRATION

This paper introduces a series of papers describing the validation of data products from the improved stratospheric and mesospheric sounder (ISAMS) on the Upper Atmosphere Research Satellite. ISAMS is a limb-so unding infrared gas-correlation radiometer, measuring thermal emission from a range of constituents. The constituents measured are ozone, wa ter vapor, methane, nitrous oxide, nitric oxide, nitrogen dioxide, nit rogen pentoxide, nitric acid, carbon monoxide, and aerosol. Atmospheri c temperature and composition data were obtained for approximately 180 days between September 26, 1991, and July 29, 1992, with near-global coverage. The instrument and the retrieval process are briefly describ ed, together with aspects of the validation process relevant to all da ta products, including the radiometric calibration and the analysis of the calibrated radiances to produce data on a standard time-altitude grid.