近半个世纪云南持续数年干旱事件时空分布

The Temporal and Spatial Distribution of Multiyear Drought Events in Yunnan During the Last half-Century

云南近五十年气候变化趋势与规律研究对于理解和预测区域气候对全球暖化的响应有重要意义.研究基于云南29个气象站点1960-2012年的日降水数据,进行了标准化降水指数(SPI)分析,探讨了过去近五十年云南SPI24的变化趋势,以此确定了三次持续数年的干旱事件,分析了它们的空间演化模式和可能成因.分析结果表明,过去半个多世纪云南降水存在明显的年代际变化规律和变旱变涝趋势;分别在1988-1990年、2004-2007年和2009-2012年经历了三次持续数年的干旱事件.其中1988-1990年和2009-2012年的干旱事件在空间分布模式上表现为以滇南和滇东中部为中心地,向外发展而成覆盖云南大部分的极端干旱;而2004-2007年的干旱区域呈点状分布.在机制方面,持续数年干旱事件可能与大气环流异常持续发展并且受到某一特殊海气模式加持有关.

It is important to study the climate trends and patterns of Yunnan in the recent half century for understanding and predicting regional 1960--2012 daily precipitation rainfall data from 29 response to global climate warming. Using meteorological stations in Yunnan, we con- duct standardized precipitation index （SPI） analysis to reveal change trend of SPI in Yunnan, de- tect multiyear drought events, and elucidate their evolutions of spatial patterns and possible cau- ses. Analysis results showed that SPI values in Yunnan exhibit an obvious interdecadal oscilla- tions and Yunnan has experienced three multiyear drought events in 1988--1990,2004--2007,and 2009--2012. The evolutions of three events are different. 1988--1990 and 2009--2012 drought e- vents started from southern Yunnan and central part of eastern Yunnan as their drought center respectively, and then developed to extreme droughts covering most of Yunnan;the spatial modes of 2004--2007 drought event exhibited as dotted patterns. Three multiyear drought events may be related to sustained development of the atmospheric circulation anomalies and associated with some ocean-atmosphere coupling.