LONG-TERM VARIATION OF UPPER STRATOSPHERIC CIRCULATION IN THE NORTHERN-HEMISPHERE IN DECEMBER

Long-term variation of the mean zonal wind in the upper stratosphere in December is investigated using NMC geopotential height data from 1979 to 1987. The period of analysis is anteriorly extended until 1973 by combining the results of various investigators. It was found that the mean zonal wind at 1 mb, 40°N shows outstanding long-term variation of the order of 10 years. Similar variation was also found in the rocket measurement of east-west wind component at Ryori (39°N, 142°E). It is shown that the long-term variation of the mean zonal wind has a good correlation with the solar activity, ozone partial pressure and solar UV index. © 1990, Meteorological Society of Japan.