我国大陆上空可降水量的时空变化特征  

Spatial-temporal variations of precipitable water over China

作　　者：戴莹[1] 杨修群[1] 

机构地区：[1]南京大学灾害性天气气候研究所,南京210093

出　　处：《气象科学》2009年第2期143-149,共7页Journal of the Meteorological Sciences

基　　金：公益性行业(气象)科研专项项目(GYHY200706005);国家973项目(2004CB418303);国家自然科学基金项目(40730953;40425009)

摘　　要：利用1958—2001年NCEP/NCAR和ECMWF月平均再分析资料,由地面积分到300 hPa计算了我国大陆上空整层大气的可降水量,对可降水量的时空变化规律及我国大陆上空可降水总量变化特征进行了分析,并利用部分站点探空资料对大气再分析资料获得的结果进行了校验。结果表明:我国大部分地区年平均可降水量表现为减少趋势,而西北地区和华南沿海呈增加趋势;各个季节平均可降水量趋势变化特征并不相同;去除线性趋势的可降水量异常变化主要表现为全国大部分地区一致的年代际振荡,在1965年可降水量由偏多向偏少转变,而在1987年前后可降水量又由偏少向偏多转变;我国大陆上空年平均可降水总量的变化特征主要表现为从1960s中期的持续减少和大致从1980s后期的增加趋势特征。The precipitable water （PW） integrated vertically from surface to 300 hPa over China is estimated with monthly data taken from both NCEP/NCAR and ECMWF reanalysis for 1958-2001. The spatial-temporal variations of the PW are examined and some results are compared with those estimated with the radiosonde observations at selected stations. It is shown that the annual mean PW is characterized by a decreasing linear trend over most of China except over northwestern China and the coastal regions of southern China where the PW has an increasing trend. The linear trend of the PW differs from one season to another. Mostly significant linear trend in the PW changes is found during summer when the PW tends to increase over Yangtse river valley, southern and northwestern China and decease over other regions of China. The PW tends to increase during winter but decrease during spring and autumn over most of China. The leading EOF for the detrended PW anomaly exhibits a decadal mode with obvious phase transitions around 1965 when the PW has a decreasing shift and around 1987 when the PW has an increasing shift. The total PW over China has a similar feature.

关 键 词：可降水量 时空变化 EOF 

分 类 号：P468.024[天文地球—大气科学及气象学]