长江中下游地区典型旱涝急转气候特征研究

CLIMATE CHARACTERS OF TYPICAL DROUGHTS-FLOODS ABRUPT ALTERNATION EVENTS IN THE MIDDLE-LOWER REACHES OF THE YANGTZE RIVER

为了研究长江中下游的旱涝急转气候特征,利用标准化降水指数和灾情资料挑选出了1960～2011年长江中下游各水资源二级分区的典型旱涝急转事件,在此基础上分析了其时空分布特征、各区频次和强度的差异,以及旱涝急转期间的大气环流形势。结果表明:长江中下游在这52a中共有5a出现了典型的旱涝急转事件,约10a一遇;其中下游干流的旱涝急转事件强度指数更大、涝期降水量更大。旱涝急转前后的大气环流发生了明显的调整,200hPa高度场上的南亚地区、东亚高纬地区和850hPa风场上的东亚副热带地区存在显著的差异。

Using standardized precipitation index and historical disaster data,droughts-floods abrupt alternation events in second-level hydrology partition of middle-lower reaches of the Yangtze River were selected,their spatio-temporal distribution characters and the differences in frequency and intensity of partitions were also analyzed.The results showed that from 1960 to 2011 typical droughts-floods abrupt alternation events happened,the frequency was about 10 years,in which the intensity index and rainfall intensity in lower main reaches were stronger.There were obvious adjustments when droughts-floods abrupt alternation events happened.There are notable differences in south and east Asian high latitude areas of 200 hPa height field and subtropical east Asian areas in 850 hPa wind field.