近50年长江中下游地区夏季气温变化与东半球环流异常  

Summertime Temperature Variations in the Middle and Lower Yangtze River and Their Related Circulation Anomalies in the Eastern Hemisphere in the Past Five Decades

作　　者：蔡佳熙[1,2] 管兆勇[1,2] 高庆九[1,2] 林昕[3] 钱代丽[1,2] 

机构地区：[1]南京信息工程大学大气科学学院,南京210044 [2]江苏省气象灾害重点实验室,南京210044 [3]福建省气候中心,福州350001

出　　处：《地理学报》2009年第3期289-302,共14页Acta Geographica Sinica

基　　金：国家科技支撑计划课题(2007BAC29B02);江苏省气象灾害重点实验室资助项目(KLME060101)~~

摘　　要：采用中国气象局整编的气温资料以及NCEP/NCAR再分析资料,分析了1960-2005年中国长江中下游地区夏季气温变化与东半球环流异常的联系。结果表明:近50年来,中国长江中下游地区夏季气温呈现出明显的非对称趋势变化特征,夏季气温的上升趋势在很大程度上是日最低气温上升带来的结果;典型高、低温年,在环流场的垂直分布均呈准正压结构的情况下,从对流层低层一直到高层,东半球大部分区域的异常值符号相反。此外,出现在江淮流域上空的异常环流的形成和维持可能与三支不同源头的波列有关;地面长波辐射对气温的影响在夜间超过白天,气温分别与感热通量和潜热通量呈负相关以及正相关关系;典型高(低)温年,垂直温度平流引起的异常动力增(降)温和非绝热加热引起的异常增(降)温可以作为解释高(低)温年气温异常维持的原因。Using the data of daily temperature from China Meteorological Administration and the NCEP/NCAR reanalysis data, we analyze the relationships between the summertime high/low temperature events in the middle and lower Yangtze River and the related circulation anomalies in the Eastern Hemisphere from 1960 to 2005. The summer temperature shows a significantly increasing trend, which are explained by the rise of daily minimum temperature in the past 50 years. In the major regions, the opposite scenarios are observed circulation anomalies in lower and upper parts of the troposphere in the years when the temperatures are higher than normal, as compared to those in the years when the temperatures are lower than normal in the middle and lower Yangtze River. The emergence and maintenance of the anomalous circulations are found to be related to three wave train related teleconnection patterns. The anomalous circulation structure in vertical direction in both the high and lower temperature years are barotropic. Influences of the long wave surfaxe radiation on the air temperature are found to be stronger in the nighttime than in the daytime. Both the maximum and minimum temperatures have negative relationships with the sensible heat flux but positive relationships with the latent heat flux. To some extent, the anomalous dynamic heating （cooling） caused by the vertical thermal advection as well as the diabatic heating （cooling） caused by diabatic processes can explain the formation of the high （low） temperature events in the middle and lower Yangtze River in boreal summer.

关 键 词：长江中下游 夏季气温变化 环流特征 

分 类 号：P467[天文地球—大气科学及气象学]