The Change Features of Atmospheric Circulation in Seasonal Transition Period

Using the data of NCAR /NCEP monthly reanalysis data from 1961 to 2007, seasonal changes of atmospheric circulation over the Tibetan Plateau and the atmospheric circulation system which has affected by Tibetan Plateau are analyzed, thus proving the reasonability of the seasonal division method. Seasonal changes of geopotential height, wind field, air temperature, and rainfall over Tibetan Plateau, are consistent with seasonal changes which made by plateau universality season division method. Besides, Asia high pressure, subtropic high air pressure and subtropic westerly jet are consistent with seasonal change which made by the seasonal division method too. All of this shows the plateau universality season division method is reasonable. Seasonality of wind field (500hPa、100hPa) gets close to the equator with geographic height rising. Seasonality of wind field is primarily connected with change of East Asia monsoon. Seasonality of atmospheric circulation proves the seasonal change of general atmospheric circulation, and proves the reasonability of plateau universality season division method.