【摘要】 选取江浙沪地区1960—2008年22个气象台站汛期(4—9月)的逐月降水数据,利用经验正交函数(EOF)方法分析了该地区汛期降水的时空分布特征及旱涝状况.结果表明,江浙沪地区汛期降水可分为4种类型:全区偏涝(旱)型、南涝(旱)北旱(涝)型、东涝(旱)西旱(涝)型、中心涝(旱)南北旱(涝)型;1960—1987年以全区偏旱型为主,1988—2008年以南涝北旱型为主.通过已有研究成果对各年旱涝气候特征的比较分析发现,全区偏涝型主要受大范围大气环流异常的影响,全区偏旱型与副高的强度、范围和副高脊线位置等有关,厄尔尼诺事件的同年或次年通常会出现南旱北涝降水类型,东旱西涝降水类型主要受副高和西风带移动影响,中心旱南北涝型主要受到台风的影响而出现.更多还原

【Abstract】 Monthly precipitation data from 22 meteorological stations in the Jiangsu-Zhejiang-Shanghai district in flood season(April to September)from 1960-2008 were used to analyze temporal and spatial distribution of precipitation,drought and flood by Empirical Orthogonal Function(EOF)analysis.It was found that precipitation could be divided into 4types:whole region flood(drought),south flood(drought)-north drought(flood),east flood(drought)-west drought(flood),central flood(drought)-south and north drought(flood);The years of 1960-1987 and 1988-2008 were dominated by whole region flood and south floodnorth drought,respectively.Comparative analysis of past works on climatic characteristics revealed that whole region flood was mainly affected by anomalies in atmospheric circulation;Whole region drought was mainly affected by intensity,scope and ridge line location of subtropical high;South drought-north flood often occurred in the same year as or the year following El Nino events;East drought-west flood was mainly affected by subtropical high and westerly movements;Central drought-south and north flood was mainly affected by the typhoon.更多还原