南海OLR异常与2007年广东省高温天气的关系

RELATIONSHIP BETWEEN OLR ABNORMITY OVER THE SOUTH CHINA SEA AND THE 2007 HIGH TEMPERATURE EVENT IN GUANGDONG

利用NCEP/NCAR提供的位势高度场、温度场资料和NOAA提供的OLR资料,应用EOF分析和相关分析等方法,分析南海区域(107.5°—120°E、12.5°—22.5°N)OLR的异常特征及其与2007年广东省高温天气的关系。结果表明,南海区域对100°—120°E、0°—35°N区域内OLR异常分布的主要时空型贡献最大,即该区域OLR的变率最大。OLR的分布基本可以反映出副热带高压的位置和强度,OLR值偏大、中心偏西,则副热带高压偏强、偏西。上空对流偏弱,下沉增温是造成2007年7月广东省长时间、大范围高温天气的主要原因之一。

The NCEP/NCAR geopotential height and temperature fields data and the NOAA OLR data are used to analyze the relationship between the OLR abnormity over the South China Sea （107.5°-120°E, 12.5°-22.5°N） and the 2007 high temperature event in Guangdong by employing the EOF and the correlation analysis methods. The results show that the South China Sea contributes the most to the OLR abnormity in 100°-120°E, 0°-35°N, namely the OLR in this region presents the most significant abnormity. The distribution of OLR can basically reflect the location and intensity of the subtropical high. The OLR with larger value and westward center induces the stronger and westward subtropical high. The weaker upper convection and the subsidence warming is one of the primary factors causing the July 2007 high temperature event in Guangdong.