Atmospheric Parameters Retrieved from CRISTA Measurements in the Upper Mesosphere and Lower Thermosphere

摘要

During its two missions of about one week duration each in November 1994 and in August 1997 the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) experiment observed spectrally resolved mid- and far-infrared emissions from the earth limb in the altitude regime from the troposphere to the lower thermosphere. The measurements concentrated on high spatial resolution in all three dimensions in the lower part of the height range. At upper mesosphere/ lower thermosphere altitudes global ozone concentrations during day and night, daytime carbon-dioxide densities, and atmospheric temperatures were derived using a comprehensive non-LTE model. The derived parameters compare well with other experimental data. Pronounced horizontal structures in latitude as well as in longitude are found in all parameters showing that dynamical influences are of importance also in the upper mesosphere/lower thermosphere. Carbon dioxide mixing ratios start to depart from their tropospheric values at altitudes as low as 70-80 km. Atmospheric temperatures of 140K and below were retrieved near the menopause at high northern latitudes in August. These data are supported by the simultaneous observation of polar mesospheric clouds.