Stratospheric Ozone in Low-Latitude Northern Hemisphere in April 1984

Abstract

The Institute of Space and Astronautical Science Sagamihara-shi 229 Japan The stratospheric ozone significantly protects the life from the harmful ultra-violet solar radiation. In a broad way, stratospheric ozone is produced in a low-latitude region, transported to polar regions, stored, then becomes extinct there. The decrease in ozone concentration in the antarctic region is watched in recent years, but the ozone trend in the low-latitude region, which is the ozone yielding region, is no less important. Dutch's model in 1966 indicates that the total column ozone in the low-latitude northern hemisphere in April is less in the half-circle region around 180°of longitude than in the half-circle region around 0°, and there is the high-density region around 90°. The cause for this distribution has not been manifested yet; They suppose that it is due to topographical effects on the atmospheric circulation. In the present study, we analyze the stratospheric ozone distribution in the low-latitude northern hemisphere by using the data from LAS (Limb-Atmospheric Infrared Spectrometer), which was born on the satellite "OHZORA" (EXOS-C). We confirm that the longitudinal distribution of the total column ozone near surface is essentially in good agreement with Dutch's model and TOMS data. We could obtain the distribution maps at various altitudes. The altitude distribution indicates that the longitudinal variation is large at 40 km and 30 km, where the chemical process in ozone production is important. The longitudinal distributions at these altitudes are very similar to the total ozone distribution. This results indicate that the ozone distribution cannot be explained only by the topographical effect on the atmospheric circulation, and that longitudinal effects on the ozone chemistry in the upper stratosphere are significant. A hypothetical model is described for the present results.