Latitude distribution of ozone at high altitudes, deduced from a satellite measurement of the Earth's radiance at 2840 A

Abstract

The radiance of the earth's daylit atmosphere at 2840 A has been measured with a satellite-borne radiometer as a function of latitude, along the 2 o'clock meridian, and as a function of angle of insolation. The data are compared with the expected radiances calculated using three different ozone distributions, the Altshuler and Elterman models and the 1949 NRL measurement (corrected) of Johnson et al. The Johnson data lead to the closest agreement, but the radiance is still about 50% higher than our measurements—implying a total ozone concentration above 35 km about twice that of Johnson's. Using the relation between radiance and ozone concentration, the data are analyzed to give the latitude distribution of the high-altitude (>35 km) ozone. This analysis shows that the seasonal variation of the high-altitude ozone appears to be about 6 months out of phase with the well-known seasonal variation near the peak of the ozone profile (maximum in late winter and minimum in late summer). The spectral distribution of the ultraviolet radiance calculated by a number of authors, along with the present measurement and the data of other experimenters, are summarized and compared.