A Study on the 3-dimensional Material Transport Structure Between the Stratosphere and the Troposphere in the Extratropics.

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The air entered from the troposphere to the stratosphere in the equatorial region moves toward extratropical stratosphere and returned into the troposphere in the extratropics. This circulation is important for determining ozone and water vapor distribution. These gases are essential for heat balance in the stratosphere. Under this project the understanding of the climatology and the seasonal variation of meridional circulation is greatly improved. The following are major results obtained in this project.From the vertical profiles of tracer constituents observed by the UARS satellite, the wintertime downward velocity in the Antarctic polar vortex is estimated. Also, the upward velocity in the equatorial region associated with the QBO is estimated and the phase relation between the vertical motion and the temperature is shown. Using the objective analysis data, the reverse circulation in the subtropical region associated with the QBO is shown for the first time. Also, the global circulation change after the Pinatubo eruption and the seasonal variation of downward motion in the polar regions are quantitatively obtained. It is shown that the stratospheric fountain hypothesis is not needed. The summer weather regime is analysed over the north Atlantic region. The circulation and water vapor distribution of an idealized middle atmosphere is studied.The last two points are indirect to the research theme, but' the interesting results are obtained. The 3-dimensional structure has not been clarified yet and the modeling study is not completed. However, this project is a stating point of this subject. Further study is expected.