华南“龙舟水”强度异常与大气环流和海温异常的关系分析  

The anomalous"Dragon_boat rainfall"variability in South China linked to atmospheric circulation and SST anomalies

作　　者：伍红雨[1,2] 吴遥 WU Hongyu;WU Yao(Guangdong Climate Center,Guangzhou 510641,China;Guangzhou Institute of Tropical and Marine Meteorology,China Meteorological Administration/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction,Guangzhou 510641,China;Chongqing Climate Center,Chongqing 401147,China)

机构地区：[1]广东省气候中心,广州510641 [2]中国气象局广州热带海洋气象研究所/广东省区域数值天气预报重点实验室,广州510641 [3]重庆市气候中心,重庆401147

出　　处：《气象学报》2025年第2期226-239,共14页Acta Meteorologica Sinica

基　　金：国家自然科学基金项目(42475015)、广东省灾害防治及应急管理专项。

摘　　要：每年端午节前后龙舟竞渡之时,是华南前汛期降水最多、最集中的时期,强降水常引发严重洪涝灾害。对近62年华南“龙舟水”强度异常的气候成因进行分析是防灾、减灾的迫切需求。利用1961—2022年华南192个国家级气象观测站逐日降水资料,构建一个表征华南“龙舟水”强度的年景指数,采用线性趋势分析、小波分析等方法分析其变化特征。利用NCEP/NCAR再分析资料和海表温度资料,采用相关和合成分析方法,分析了近62年华南“龙舟水”强度异常与同期大气环流和前期海温异常的关系。结果表明,近62年来,华南“龙舟水”强度年景指数具有明显的年际和年代际变化,且呈明显线性上升趋势。1993年以前主要存在4—5 a的年际变化周期,1993年后,除存在准2 a和准6 a的年际周期外,还存在准16 a的年代际周期。相关分析表明,在“龙舟水”期间(5月21日—6月20日),对流层高层北太平洋中纬度地区位势高度降低,中层东亚大槽南段偏强,华南北部位势高度降低,南支槽偏强,低层菲律宾以东异常反气旋的存在,地面鄂霍次克海阻塞高压加强、东北太平洋高压减弱有利于华南“龙舟水”偏强。“龙舟水”期间,1993年之前和之后不同年代际背景下,华南“龙舟水”异常强、弱年的大气环流存在明显差异。1993年后,高层华南上空辐散更强,低层从西太平洋、中国南海和孟加拉湾到华南的水汽输送更为突出,而北方南下的冷空气更强,致使华南的水汽辐合和上升运动更强,导致1993年后“龙舟水”强度更强。相关分析表明,上一年夏季、秋季到冬季热带大西洋海温持续偏低,上一年夏季到秋季海洋性大陆海温偏低、东北太平洋海温偏高,当年春季热带北太平洋日界线附近海温偏低,有利于华南“龙舟水”强度偏强。华南“龙舟水”异常强、弱年与前期赤道中东太平洋海温的关系具有不对The dragon boat race period around the Dragon Boat Festival every year is the period with the highest and most concentrated precipitation during the pre-flood season in South China,and heavy rainfall often leads to serious flood disasters.Analyzing climatic causes of abnormal intensity of the Dragon_boat rainfall in South China in the past 62 years is imperative for disaster prevention and mitigation.Using daily precipitation data collected at 192 national meteorological observation stations in South China from 1961 to 2022,a yearly index is constructed to characterize the intensity of the Dragon_boat rainfall in South China.Linear trend analysis,wavelet analysis,and other methods are used to analyze its changing characteristics.Using NCEP/NCAR reanalysis data and SST data,correlation and composite analysis methods are used to analyze the relationship between the intensity anomaly of the Dragon_boat rainfall in South China over the past 62 years and atmospheric circulation anomalies during the same period and preceding SST anomalies.The results show that the annual intensity index of Dragon_boat rainfall in South China has obvious interannual and interdecadal changes,while an obvious linear upward trend can be found in the past 62 years.The annual intensity index of Dragon_boat rainfall has shifted from weak before 1993 to strong afterwards.There was mainly an interannual variation cycle of 4—5 a before 1993,and there is also an interdecadal cycle of about 16 a in addition to the interannual cycles of about 2 and 6 a after 1993.Related analysis shows that during the Dragon_boat rainfall period(21 May—20 June),geopotential height in the mid-latitude region of the North Pacific decreases in the upper troposphere,the southern section of the East Asian trough in the middle troposphere is stronger,and geopotential height in northern part of South China decreases,and the southern branch trough is stronger.The presence of abnormal anticyclones to the east of the Philippines in the lower troposphere,the strengthening

关 键 词：“龙舟水” 强度 大气环流 海温 华南 

分 类 号：P426.6[天文地球—大气科学及气象学]