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The Improved Stratospheric and Mesospheric Sounder (ISAMS) is producing the first global measurements of emission from the 1 yields 0 band of nitric oxide (NO). The emission from the lower thermosphere has been examined and is seen to increase dramatically at times corresponding to high solar activity. The temporal and geographical extent of the effect is reported, and possible mechanisms for the enhanced emission are discussed. The need for adequate representation of thermospheric NO emission in order to retrieve NO number densities at all heights from ISAMS data is discussed, as are prospects for science studies using such NO number density measurements. more...

The Improved Stratospheric and Mesospheric (ISAMS) on board the Upper Atmosphere Research Satellite (UARS) incorporates a 12.1 micron window channel for the measurement of aerosol opacity. The retrieval scheme is discussed briefly and preliminary observations of the Mt. Pinatubo aerosol cloud are presented and compared with SAGE 2 observations at 1.02 microns. The effect of aerosol on other ISAMS channels and its spectral dependence is discussed. more...

The potential of the ESA Global Ozone Monitoring Experiment (GOME) to produce ozone profile information has been examined by carrying out two sample retrievals using simulated GOME data. The first retrieval examines the potential of the GOME instrument to produce stratospheric ozone profiles using the traditional back-scatter ultraviolet technique, while the second examines the possibility of obtaining tropospheric profile information, and improving the quality of the stratospheric profile retrievals, by exploiting the temperature dependence of the ozone Huggins bands. more...

The Improved Stratospheric and Mesospheric Sounder (ISAMS) is a multichannel radiometer and forms part of the science payload of the Upper Atmosphere Research Satellite (UARS). ISAMS measures infrared emissions from the Earth's atmosphere in several wavelength bands. Three such bands include emission from nitric oxide, nitrogen dioxide, and dinitrogen pentoxide. In this paper, we briefly discuss how the ISAMS instrument measures NO, NO2, and N2O5. We also present preliminary data from these channels and describe preliminary validation work. more...

Data from the 6.9-micron H2O channel and the 6.2-micron NO2 channel of the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) have been used to investigate the daytime enhancement to H2O; the high concentration of H2O sometimes observed in the polar night mesosphere; and the high ratio of daytime to nighttime NO2 in the upper stratosphere. These three phenomena deviate noticeably from the predictions of photochemical theory. The 20 to 30 percent diurnal variation in stratospheric H2O apparent in LIMS data cannot be reconciled with a photochemical lifetime in excess of four months. This is attributed to departure from local thermodynamic equilibrium of daytime emission which had not been accounted for in retrievals. Speculative possibilities of NLTE emission from the H2O nu2 and NO2 nu3 hot bands are discussed. It is found that the nonthermal emission from NO2 significantly affects retrieval of H2O in the polar nighttime and NO2 in the daytime stratosphere at low latitudes. more...