The nimbus 4 infrared spectroscopy experiment: 3. Observations of the lower stratospheric thermal structure and total ozone

Abstract

Stratospheric temperatures and total column ozone abundance obtained with the Nimbus 4 infrared interferometer spectrometer (Iris) experiment from April 1970 to January 1971 are summarized in the form of monthly mean global maps and zonal averages at the 100-, 30-, and 10-mbar levels. Although there are some systematic differences between the retrieved temperatures and the climatological means, several gross features of the thermal field in the lower stratosphere, such as the position and tilt of the major standing waves, are satisfactorily reproduced. Planetary scale wave activity as inferred from the standard deviation of the temperature (with respect to the zonal mean) shows significant differences in the lower stratosphere of the two hemispheres. Intense wave activity is observed to commence in winter over the northern polar latitudes. This wave activity persists with little attenuation with height up to 10 mbar. In the southern polar latitudes only a moderate wave activity existing essentially below 30 mbar is observed during winter. The activity intensifies in spring, however, and has an appreciable attenuation with height up to 10 mbar. Large-scale features in the global distribution of total ozone derived from Iris measurements agree with those deduced from Dobson data. However, the seasonal amplitude of total ozone at northern high latitudes is underestimated by the infrared remote sensing technique. A strong correlation between planetary waves in the temperature field and total ozone is observed, ozone increasing rapidly in the Polar Regions when the wave activity is greatest, which suggests associated transport. In the tropics the remotely sensed ozone data suggest the presence of a standing wave number one pattern with a maximum over the Atlantic Ocean and a minimum over Southeast Asia.