摘要
利用24°~35°N,104°~124°E范围内180个测站的日降水量和气温资料,计算了各季1969-2008年的综合气象干旱指数,以及3个代表站1953-2008年的Z指数,分析了近40年长江中下游地区的干旱发生频率、覆盖范围及年际变化和不同干旱强度的空间分布。结果表明,干旱覆盖范围达90%以上的事件在1980年以前主要出现在冬季,1990年代主要出现在春季,到21世纪则主要出现在夏季。春、秋季干旱有下降的趋势,而冬、夏季为增加趋势。虽然长江中下游地区冬季干旱覆盖范围在减小,但出现干旱的频率较大,说明冬季出现局部干旱的程度在增大。而夏季干旱发生频率较小,但覆盖范围正在高值期,说明夏季的旱涝程度还在加大。虽然春季发生干旱的频率较高,但多以轻旱为主,并且覆盖范围也处在下降期,因此,春季干旱应比过去有所减缓。从各方面来看,秋季出现干旱的几率最低。
The characteristics of spatial and temporal variations of drought in mid-and lower-reaches of Yangtze River basin（24°~35°N,104°~124°E） were statistically analyzed based on the observed data at 180 stations using the meteorological drought composite index from 1969 to 2008 and Z-index of 3 representative stations from 1953 to 2008,respectively.The results show that the coverage area of drought over 90% mainly occurred in winter before 1980s,in spring in 1990s and in summer in 21 century.The drought frequency decreased in spring and autumn and increased in winter and summer.The local drought events increased in winter in mid-and lower-reaches of Yangtze River basin due to the drought frequency were high though the coverage area of drought reduced.The drought and flood occurred frequently in summer because the coverage area of drought were big nevertheless the frequency of drought were lower.The drought events reduced in spring as the coverage area of drought were decreasing and the light drought dominated.The drought events in autumn were the minimum as a whole.
出处
《高原气象》
CSCD
北大核心
2010年第6期1587-1593,共7页
Plateau Meteorology
基金
公益性行业(气象)科研专项项目(GYHY201006023)资助
关键词
长江中下游地区
干旱指数
Z指数
干旱变化趋势
In mid-and lower-reaches of Yangtze River basin
Drought index
Z-index
Drought change trend
