近51年长江三角洲地区气候变化及可能原因

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

利用1960—2010年逐日气候资料,采用线性回归、累积距平和Morlet小波变换等方法,分析了长江三角洲地区近51 a的气候变化特征。结果表明,长江三角洲地区平均气温呈上升趋势,最低气温上升最快,最高气温上升较慢;年平均气温自南向北递减,沿海地区递减滞后于内陆地区;上海及杭州湾升温较快,浙江南部则相对缓慢。年平均降水量呈波动变化特点,夏、冬两季降水增加趋势明显;年平均降水量及雨日数自北向南增大,倾向率具有明显的区域性特点。年降水量存在13 a左右、6—8 a、3—4 a和1—2 a的变化周期,气温变化存在32 a以上、12 a左右、4—6 a和1—2 a的变化周期,其中两者1—2 a周期震荡能量最强。长江三角洲地区气候变化与城市化进程、海气相互作用、极涡、西太平洋副热带高压等存在显著的相关关系。长江三角洲地区气候逐渐变暖,降水呈集中化趋势,导致发生旱涝灾害的不确定性增加。

Based on 1960-201 0 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.