Because of the cold episold of SST in the east equatorial Pacific, the characteristics of the general circulation in the northern Hemisphere are as follows: the general circulations in the middle and high latitude of the northern Hemisphere are vicissitude of zonal and meridional cell; the west Pacific subtropical high is weaker, northward and eastward; the tropical convections are strong in winter and spring, and weak in summer; both the summer monsoon and the ITCZ are weak Under the influence of the climatic conditions, the typhoon is less than normal; the major rainband is located between the Yellow River and Yangtze River;drought in the north of Yellow River is severe.