近50年广东冬半年降水的变化及连旱成因  

VARIATION OF PRECIPITATION DURING WINTER HALF-YEAR AND CAUSE OF CONTINUOUS DROUGHT IN GUANGDONG DURING THE PAST 50 YEARS

作　　者：纪忠萍[1] 温晶[1] 方一川[1] 高晓容[2] 谷德军[3] 吴秀兰[1] 李茵茵[1] 

机构地区：[1]广州中心气象台,广东广州510080 [2]兰州大学大气科学学院,甘肃兰州730000 [3]中国气象局广州热带海洋气象研究所/热带季风重点实验室,广东广州510080

出　　处：《热带气象学报》2009年第1期29-36,共8页Journal of Tropical Meteorology

基　　金：广东省科技三项经费计划项目(2006A36503001);广东省科技计划项目(2007A032600002);广东省计划项目(2005B32601007);广东省气象局气象科研课题(200519)共同资助

摘　　要：利用EOF分析、小波分析、相关分析等方法,对广东近50年(1957—2006年)冬半年(当年10月—次年3月)降水的变化特征及其与太平洋海温场的关系进行了研究。结果表明,广东冬半年降水存在显著的准40年、准2年左右的变化周期,偏少阶段主要发生在1950年代末—1970年代初、1990年代末至今。冬半年发生连旱的频率远大于连涝的频率。广东冬半年降水与赤道中东太平洋的海温具有明显的正相关,与菲律宾以东的西北太平洋的海温具有明显的负相关。连续干旱年出现在Nio3.4区的海温为负、正异常年的频率分别为61.5%、38.5%。通过对冬半年异常连旱年Nio3.4区海温分别为正、负异常时的大气环流场进行合成分析,可知极涡偏弱,欧洲槽偏强,巴尔喀什湖附近的高压脊偏强,广东为一致的偏北风距平场控制,冷空气活跃,而亚洲大陆中低纬度西风带低压扰动不活跃,南支槽活动偏弱,是导致广东冬半年产生连续干旱的共同原因。The variation characteristics of precipitation during the winter half-year （between October and the next March） in Guangdong during the past 50 years （from 1957 to 2006） and its relationship with Pacific SST are studied using the methods of EOF analysis, wavelet analysis and correlation analysis. The results show that Guangdong precipitation during winter half-year exhibits quasi-periodic significant oscillations of 40 years and 2 years, and rainfall is less from the end of 1950s to the start of 1970s and from the end of 1990s to now, and rainfall is more from the mid of 1970s to the mid of 1990s. The frequency of continuous drought is more than the continuous flooding during the winter half-year. Guangdong precipitation during the winter half-year is in significantly positive correlation with equatorial central and eastern Pacific SST but significantly negative correlation with the western and northern Pacific SST east of the Philippine Sea. 61.5% and 38.5% of continuous drought happened in the phase of negative and positive anomalies of Nifio3.4 index respectively. The composed analysis of atmospheric circulation is performed with the positive and negative phase of Nifio3.4 index associated with continuous drought of Guangdong during the winter half-year. The results showed that, the weak polar vortex, strong trough in European and ridge near BaLkhash Lake, active cold air and consistent northerly winds anomaly controlling Guangdong at low levels, inactive westerly low disturbance in the low-mid latitude of Asian continent, and weak southern branch westerly trough, are mutual causes for continuous drought of Guangdong during the winter half-year.

关 键 词：连旱成因 EOF分析 冬半年降水 变化特征 

分 类 号：P426.62[天文地球—大气科学及气象学]