Abstract:There appeared some abnormal climatic phenomena such as extra long summer time and short autumn, less rain in Meiyu season, more high temperature days and continuous drought from summer to autumn in the Hangjiahu plain in 2006. Through analyzing the atmospheric circulation, it is found out that the subtropical high was stronger and more westward persistently in the West Pacific; the polar vortex was weaker than normal in the Northern Hemisphere; cold air activities were more northward and the zonal circulation prevailed in Asia in 2006. The regional abnormal climate relates to the abnormal season transition of atmosphere circulation. The abnormal atmosphere circulation can attribute to the early abnormal circulation. The continuously stronger subtropical high in the summer of 2006 is related to the stronger meridional circulation and continuously stronger subtropical high in the previous winter and spring, and the abnormal spring circulation led to the quick season transition from autumn to winter. The result of eddy height analysis shows that the abnormal westward movement of the positive eddy height center in the troposphere in May, the two positive centers generated in the stratosphere from June to July, and the abnormal stronger positive center in September altogether indicated and promoted the abnormal development of the lowerlevel atmospheric circulation in summer; therefore, the summer was longer and the transition from summer to autumn was put off; and the abnormal stronger, southward cold low and the sudden weakening of the warm high in November of 2005 led to quick transition from autumn to winter and short autumn.
