长江中下游气候的长期变化及基本态特征

研究了1885年以来，我国长江中下游四季及年降水量，四季及年平均气温的长期变化，指出长江中下游四个季及年的总降水量（平均气温）都是正的趋势，但有季节的差异，春季是升温同时增雨最显著的季节，还研究了我国长江中下游降水与气温的气候基本态及气候变率的特征及时间演变规律，指出，60年代以后夏季气温变化的异常程度几乎比以前大了一倍，在冬季，近期在暖背景下的冬季气温变率变小的特征表明长江中下游可能出现持续发暖冬特征，还指出，80年代后我国的长江中下游存季降水处于高基本态与高气候变率时段，应注意频繁发生的夏季洪涝灾害，研究还指出，长江中下游夏季降水与印度季风的气候基本态反相关密切，印度季风及东亚夏季风与长江中下游夏季气温变化在各种尺度上有明显的正相关。

CLIMATE SECULAR CHANGE AND BASE STATE OVER THE MID-LOWER REACHES OF YANGTZE RIVER

In the present paper secular change in seasonal and annual rainfall and mean temperature over mid to lower reaches of the Yangtze River since 1885 is invethatgated. Re- sults show that their trends are positive with seasonal differences,and that spring is an ap- parent season both temperature rising and rainfall. The climate base state of rainfall and tem- perature along with its climate variability features and time evolution over the mid to lower of the Yangtze reaches has also been examined. The results indicate that the summer temper- ature anomaly subsequent after the 1960s is sometimes two fold as high as before;the lower wintertime temperature variability in the recent warm background shows that a period of warm winter persistence is likely to be in the reaches;the summer rainfall there is in a phase of high base state and high climate variability after the 1980s so that we must be aware of frequent occurrence of summer flood/drought events;the summer rainfall is in close anti- correlation with the climate base state of Indian monsoon and the Indian and east Asian sum- mer monsoons are in strongly positive correlation with the summer temperature of the reach- es on range of time scales.