浙江省干湿状态的时空分布特征

应用帕默尔干旱指数（PDSI）及作物湿度指数（CMI）对浙江干旱过程进行诊断，认为PDSI指数不能准确监测浙江具体干旱过程但能反映浙江长期干旱或湿润的气候状态，而CMI指数则能准确监测跟踪具体的干旱发生发展过程。在此基础上选取浙江41个气象站，计算1961-2006年各站逐月PDSI指数值，对PDSI指数值应用经验正交函数（EOF）分解后发现，浙江中部干湿变化比较剧烈，而南部和北部变化相对较弱，有南旱北湿或南湿北旱特点，西部与东部也有干湿反向变化特征；近50a来，浙江有两个阶段处于明显的气候干燥期，20世纪60年代初-70年代初和2003年至今，目前仍处于干燥期内。

Characteristics of Spatial and Temporal Distribution of Dryness/Wetness Status in Zhejiang Province

Palmer Drought Severity Index(PDSI) and Crop Moisture Index(CMI) were applied to diagnose drought process in Zhejiang Province.The results showed that long term climatic dryness/wetness events were captured by PDSI,and short term drought course of events by CMI.The monthly PDSI over the 41 observational stations in Zhejiang from Jan.1961 to Dec.2006 were analyzed with Experiential Ortho Function(EOF) method.The ranges of dryness/wetness in the middle Zhejiang were larger than in north and south parts.Converse changes of the dryness/wetness were found between the north and south,as well as between east and west parts because of geographical influence.Two clear dryness periods since 1961 were found,which occurred during early 1960's to early 1970's and during 2003 and present days respectively.