Hrdi / The Uars Data Analysis Of East Asian Regional Middle Atmosphere Zonal Wind Climate Characteristics

In this paper, the long term mean characteristics of the zonal winds in the middle atmosphere over East Asia were studied by using the HRDI/UARS measurements. The results of 7-years averaged data analysis showed that the middle atmospheric zonal winds exhibit significant regional features when compared with the CIRA-86 counterpart that has been widely used. In the region, the winter mesospheric westerly jet lies at 75 km altitude and in between 25°N—35°N, which is 10 km higher than and 5° in latitude to the south of that of the CIRA-86. While not shown in CIRA-86, there is a clear easterly band extending from the equator to high latitudes at the altitude of lower thermosphere in autumn.Further investigation revealed the presence of considerable regional scale disturbances in the whole of the middle to upper atmosphere over East Asia, except the situations in mid-latitudes in summer. In winter, the tropical lower thermospheric zonal winds fluctuate significantly in zonal direction, and this kind of the zonal disturbances extend downward to 55 km altitude (the lower limit of the observation mode of the satellite instrument) in summer. With respect to the situation in mid-latitudes, very few zonal fluctuation can bee seen in the zonal winds from 55 km to 115 km altitude range in the summer season, however, the winter mesospheric and lower thermospheric zonal winds are disturbed prominently in the zonal.