Abstract. The Measurement of Air Pollution From Satellites (MAPS) experiment flew as a payload aboard the space shuttle during April and October 1994. The instrument and the data reduction procedure were modified from earlier flights in 1981 and 1984. The modifications to both are described, and selected portions of the data are compared to concurrent aircraft borne direct measurements that had been carefully intercalibrated. In addition, the data acquired in 1984 were reprocessed using the new data reduction procedure, and the reprocessed data were compared to aircraft data acquired in 1984. The results of these comparisons indicate that the large bias error in the 1984 MAPS data has been reduced to about 10%. IntroductionCarbon monoxide (CO) is a key gas in the photochemistry of the global troposphere. It is the major sink for the OH radical, and as a result, increased emissions of carbon monoxide may lead to decreases in the level of tropospheric OH. Since OH is the principal oxidizer of the reduced species in the troposphere, increased CO emissions could lead to increased concentrations of gases like methane. These increases would impact both the planetary heat balance and the chemistry of ozone in the stratosphere. The major sources of CO are both natural and anthropogenic. The naturally produced CO results primarily from the oxidation of methane and other hydrocarbons. The anthropogenically produced CO usually results from the combustion of fossil fuels in the northern hemisphere and the burning of biomass in the tropics. The chemical lifetime of CO varies from about one-tenth year in the tropics to about 1 year in the wintertime polar regions. As a result, it is transported long distances from its sources, and the mixing ratio varies widely over the planet. Because of this, CO is an ideal candidate for measurement from an orbiting platform.The This paper first describes the modifications made to the MAPS instrument prior to the 1994 flights. Second, the modified data reduction process is discussed. Finally, the data acquired in 1994 and the reprocessed data acquired in 1984 are compared to concurrent aircraft measurements in order to estimate the accuracy of the data. MAPS Instrument Instrument Operating PrincipleThe MAPS instrument is a nadir viewing gas filter radiometer that operates in the region of the 4.67/•m carbon monoxide fundamental band. It operates on the principle of the selective chopper radiometer label et al., 1970]. That is, it produces its signal by forming the difference between the incoming energy as seen through a cell of fixed length that contains the gas of interest and a second cell that is either evacuated or that contains a nonabsorbing gas. As shown schematically in Figure 1

Abstract. Aerosol backscatter coefficients were calculated using multiwavelength aerosol extinction products from the SAGE II and III/ISS instruments (SAGE: Stratospheric Aerosol and Gas Experiment). The conversion methodology is presented, followed by an evaluation of the conversion algorithm's robustness. The SAGE-based backscatter products were compared to backscatter coefficients derived from ground-based lidar at three sites (Table Mountain Facility, Mauna Loa, and Observatoire de Haute-Provence). Further, the SAGE-derived lidar ratios were compared to values from previous balloon and theoretical studies. This evaluation includes the major eruption of Mt. Pinatubo in 1991, followed by the atmospherically quiescent period beginning in the late 1990s. Recommendations are made regarding the use of this method for evaluation of aerosol extinction profiles collected using the occultation method.

Abstract. Aerosol backscatter coefficients were calculated using multi-wavelength aerosol extinction products from the SAGE II and SAGE III/ISS instruments. The conversion methodology is presented followed by an evaluation of the conversion algorithm's robustness. The SAGE-based backscatter products were compared to backscatter coefficients derived from ground-based lidar at three sites (Table Mountain Facility, Mauna Loa, and Observatoire de Haute-Provence). This evaluation includes the major eruption of Mt. Pinatubo in 1991 followed by the atmospherically quiescent period beginning in the late nineties. Recommendations are made regarding the use of this method for evaluation of aerosol extinction profiles collected using the occultation method.

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<p>The Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument installed on the International Space Station (ISS) has completed almost half of a decade of data collection and production of science data products. The SAGE III/ISS is a solar and lunar occultation instrument that scans the light from the Sun and Moon through the limb of the Earth’s atmosphere to produce vertical profiles of aerosol, ozone, water vapor, and other trace gases. It continues the legacy of previous SAGE instruments dating back to the 1970s to provide data continuity of stratospheric constituents critical for assessing trends in the ozone layer. This presentation shows how SAGE III/ISS aerosol and gas vertical profiles continue to benefit a worldwide database of in situ and satellite data for climate observation.</p>