CLIMATE CHANGE AND POSSIBLE REASONS IN YANGTZE RIVER DELTA REGION IN RECENT 50 YEARS

Based on 1960—2010 daily temperature and precipitation data of 27 meteorological stations in Yangtze River Delta region,linear regression method,accumulative anomaly method and Morlet wavelet analysis method were used to analyze the characteristics of climate change.The results showed that:(1)The annual average temperature increased significantly,and the annual average minimum temperature increased faster than the annual average maximum temperature.The annual average temperature decreased from south to north,but that in the coastland decreased slower than that in the inland.The temperature in Shanghai and Hangzhou Bay increased rapidly while that in the southern Zhenjiang increased relatively slowly.(2) The annual precipitation presented fluctuation characteristics,however,the precipitation increased obviously in summer and winter.The annual precipitation increased from north to south,and the tendency rate presented obviously regional characteristics.(3) The annual precipitation had the variation periods of about 13-year,6—8 year,3—4 year,and 1—2 year,and the annual average temperature had the variation periods of about 32-year,12-year,4—6 year,2—3 year,and 1—2 year.(4) The climate change in Yangtze River Delta region significantly related with urbanization,air-sea interaction and the main synoptic systems(such as polar vortex index and the western Pacific subtropical high index).The climate warming and the centralized precipitation in Yangtze River Delta region resulted in more drought and flood disasters.