Abstract:

Based on upper-level air temperature radiosonde data obtained from 13 stations in East China (including six provinces and one city) from 1961 to 2017, we analyzed the spatiotemporal characteristics of upper-level air temperature at 850 hPa, 500 hPa, and 200 hPa in this region.The results showed that an obvious warming trend can be observed in the middle-lower troposphere and at the troposphere top, and between them, such trend becomes weak gradually with increasing height.Annual mean upper-level air temperature at 850 hPa and 500 hPa exhibits a "decrease first and then increase" variation, while it at 200 hPa persistently increases during the studying period.During autumn and winter, air temperature at all levels shows a significant warming trend, most obviously in winter, whereas a weak cooling trend is observed at 500 hPa in spring and 200 hPa in summer.The spatial distribution of annual mean temperature at different levels differs from the north to the south.The temperature difference between the north and the south increases first and then decreases with the increase of height.Annual mean air temperature at 850 hPa and 500 hPa has a stronger warming trend in the coastal area than in the inland area, while it at 200 hPa has a stronger warming trend in the southern area than in the northern area.In all seasons at 850 hPa, the warming trend in the coastal area is stronger than that in the inland area, and sometimes the inland area even exhibits a cooling trend.In spring at 500 hPa and summer and autumn at 200 hPa, a warming trend exhibits in the southern region, and a cooling trend is observed in the northern region in East China.

Key words: Radiosonde data, Upper-level air temperature, Annual mean temperature, Seasonal mean temperature