太平洋SSTA对广东前汛期极端降水事件影响的机制分析  

ANALYSIS OF THE MECHANISM OF PACIFIC SSTA INFLUENCING EXTREME RAINFALL PRECIPITATION EVENTS IN ANNUALLY FIRST RAINING SEASON IN GUANGDONG

作　　者：黄茂栋[1,2] 廖仕湘 张晨辉 

机构地区：[1]南京大学大气科学系,江苏南京210093 [2]梅州市气象局,广东梅州514021

出　　处：《热带气象学报》2009年第4期413-420,共8页Journal of Tropical Meteorology

摘　　要：利用国家气候中心提供的1960—2004年太平洋SSTA和广东省23个台站逐日降水资料,采用SVD方法对太平洋SSTA和广东省极端降水事件进行了时滞耦合,着重分析了太平洋SSTA对广东前汛期降水的影响机制。结果表明:太平洋SSTA变化与广东前汛期极端降水事件的变化有着显著的相关关系。热带西太平洋是影响广东前汛期极端降水事件的关键区,如果该海域前期秋季SSTA为正异常,次年前汛期高层盛行异常偏南风,而低层盛行异常偏北风,使得前汛期达到广东地区的水汽偏少,造成前汛期极端降水事件偏少,而异常冷年正好相反。赤道中东太平洋也是影响广东前汛期极端降水事件的关键区,该海域前期秋季SSTA处于正异常时,次年前汛期500 hPa高度场表现为WP遥相关型(太平洋西部遥相关型),这样从秋季到次年前汛期西太平洋高压偏强,次年前汛期广东东部及南部地区容易受副高控制,极端降水事件呈偏少趋势,广东偏北区域容易受副高西北侧暖湿气流和北方冷空气交汇影响,极端降水事件有偏多倾向,而异常冷年正好相反。Based on the data of 1960--2004 Pacific SSTA provided by the National Climate Center （NCC） and daily precipitation from 23 weather stations in Guangdong Province, the SVD method is used to conduct time-delayed couplings between the Pacific SSTA and extreme precipitation events （EPS） in Guangdong, with the focus on the influencing mechanism of Pacific SSTA for the rainfall in the annually first raining season （from April to June） in the province. Results show that they are significantly correlated and the tropical western Pacific is a key region that affects the Guangdong EPS. With positive SSTA in the key region during the preceding autumn, anomalously south （north） winds will prevail in the upper （lower） levels of the atmosphere in the current raining season so that less water vapor will be transported to Guangdong to result in less EPS, and opposite is true with negative SSTA. Furthermore, the middle and east equatorial Pacific is also a key area for the EPS in Guangdong. With positive SSTA during the preceding autumn in the middle and east equatorial Pacific, the 500 hPa geopotential height field will be marked by the WP teleconnection pattern in the current raining season, resulting in a strengthened and extended western Pacific subtropical high from autumn to the following spring, making it more likely for the east and south Guangdong to be influenced by the western Pacific subtropical high in the raining season and the EPS to have a decreased tendency, while making it more probable for the north Guangdong to be affected by warm and wet flows from the north side of the western Pacific subtropical high and the EPS to have an increased trend; the opposite is true with negative SSTA in the middle and east equatorial Pacific.

关 键 词：气候学 极端降水 时滞耦合 太平洋SSTA 前汛期 

分 类 号：P434.4[天文地球—大气科学及气象学]