Analysis of the February 2015 Atmosphere Circulation and Weather
The main characteristics of the general atmospheric circulation in February 2015 are as follows. There is one polar vortex center in the Northern Hemisphere, stronger than usual. The atmospheric circulation is in a fourwave pattern over midhigh latitudes. The West Pacific subtropical high is weaker than usual and the south branch trough is almost at the same position as normal. The monthly mean temperature is -0.2℃, 1.5℃ higher than normal. The monthly mean precipitation is 16.3 mm, which is 6.3% less than normal. Two strong cold air processes are experienced in this month, and northeast of China has one heavy snowfall process. Starting from the second half of February, more rain and snow events visit wide range of Southern China, while two haze or fog events and one sand and dust weather appear in the central and eastern part of China.