On the basis of a careful comparison of routine satellite observations in the 1980s with the CIRA-1986 models as being representative of observations in the 1970s, long-term variations of stratospheric circulations are investigated. In most parts of the stratosphere, cooling occurs, independent of the month, while warming occurs in some places. In particular, warming in winter is conspicuous over the south polar region of the middle stratosphere. The non-uniform changes of temperature fields bring about changes of temperature gradients and zonal mean zonal winds : the westerly polar night jet becomes strong in the winter hemisphere while the easterly jet becomes weak in the summer hemisphere. In the southern hemisphere winter, wave activities become weak, corresponding to the strengthening of the polar night jet.
All Science Journal Classification (ASJC) codes
- General Environmental Science
- General Engineering
- Atmospheric Science
- General Earth and Planetary Sciences