Analysis of the March 2021 Atmospheric Circulation and Weather
The main characteristics of the general atmospheric circulation in March 2021 are as follows. There were two polar vortex centers in the Northern Hemisphere, the 500 hPa geopotential height presented the distribution of a threewave pattern in the midhigh latitude of Northern Hemisphere. The strength of Western Pacific subtropical high was closed to that in normal years, and the south branch though was a little weaker. The national average temperature in March was 6.6℃, 2.5℃ higher than the normal (4.1℃) and recorded the second highest in the same period since 1961. The monthly mean precipitation amount was 27.8 mm, 6% less than in normal period (29.5 mm). There were three largescale sanddust weather processes in March, which were more and stronger than the usual, of which the sanddust weather in 13-18 was the strongest sanddust weather process in the past 10 years. A severe convective weather process occurred in the Yangtze River Basin at the end of the month, causing severe weather such as hail and thunderstorm. During this month, cold airs were weak, and only one moderate cold wave process appeared in 15-17. The droughts continued in Yunnan Province, droughts appeared and developed in South China.