夏季南亚高压和西太副高活动特征指数与中国东部降水分布的联系  

Association between Summer Activity Characteristic Indices of the South Asia High and the West Pacific Subtropical High and Precipitation Distribution in Eastern China

作　　者：雷显辉 宋敏红 张少波 LEI Xianhui;SONG Minhong;ZHANG Shaobo(School of Atmospheric Sciences,Chengdu University of Information Technology/Plateau Atmosphere and Environment Key Laboratory in Sichuan Province,Chengdu 610225,Sichuan,China)

机构地区：[1]成都信息工程大学大气科学学院,高原大气与环境四川省重点实验室,四川成都610225

出　　处：《高原气象》2022年第2期489-501,共13页Plateau Meteorology

基　　金：第二次青藏高原综合科学考察研究(2019QZKK0103);国家重点研发计划项目(2018YFC1505700);成都信息工程大学科研基金项目(KYTZ201721)。

摘　　要：为了进一步研究夏季南亚高压(South Asia High,SAH)与西太平洋副热带高压(West Pacific Subtropical High,WPSH)活动特征指数变化及其互动作用对我国东部降水的影响,利用2001-2020年高分辨率ERA5再分析资料分析了南亚高压和西太副高的夏季逐候强度指数、面积指数、脊线位置和东西伸脊点的演变特征,并针对两者同强同弱和经纬向位置远近情形下对比分析了两者互动作用对我国东部降水的影响。结果表明:(1)南亚高压和西太副高的强度指数与面积指数变化均呈较明显的正相关,特别是南亚高压的脊线位置、强度指数和面积指数的变化有较好的一致性,即:南亚高压脊线越偏北(南),其强度和面积指数均越大(小)。(2)夏季南亚高压东伸脊点和西太副高西伸脊点的逐候平均位置变化具有“相向而行、相背而去”的互动趋势,南亚高压纬向位置的突变晚于经向位置的突变,间隔时间约4候。(3)两者同强同弱年与我国东部降水有较好的相关性,即当两者同时偏强(弱)时,长江中下游地区降水偏多(少),华南地区降水偏少(多)。两者经纬向相对位置的异常对我国东部降水有一定的影响,即:当两者经纬向异常靠近时,黄河下游至出海口区域降水偏多,江南、西南地区降水偏少;而当两者经纬向异常远离时,西南地区降水偏多,长江中下游地区降水偏少。In order to further study the characteristic indices and their interactive function based on ERA5 reanalysis data from the European Centre for Medium-term Weather Forecasts(ECMWF)from 2001 to 2020 with the horizontal resolution of 0. 25° ×0. 25°,the intensity index,area index,ridge position and east-west extension ridge point of the South Asian High(SAH)and the West Pacific Subtropical High(WPSH)are calculated in summer by statistical methods. And the distance of the relative position of the longitude and latitude and the same strong and weak years in summer are selected. The influence of their cooperation on the summer precipitation in eastern China is studied by the comparative analysis. The results show as follow:(1)There is a good positive correlation between the intensity index and the area index of the SAH and the WPSH in summer. The pentad changes of the ridgeline position of the SAH is very well related to changes in its intensity and area indices. Better consistency,the more north(south) the SAH deviates,the larger(smaller) its intensity and area are.(2)The changes in pentad of the east-west ridge point between the WPSH and the SAH have a trend of "going towards each other and going away from each other". Under the temporal changes,the sudden change of the zonal position of the SAH is later than that of the meridional position. The interval time of the sudden change is about4 pentads/20 days.(3)When the SAH and the WPSH are both strong(weak),the rainfall in the middle and lower reaches of the Yangtze River is much(less),and the rainfall in South China is less(much). When their latitudes and longitudes are abnormally close,there is less precipitation in the overlapping area,more precipitation on the northern side of the overlapping area,and the precipitation band is generally zonal. The area from the lower reaches of the Yellow River to the sea estuary has more precipitation,and the precipitation in the south of the Yangtze River and South China less. When their latitude and longitude directions are ab

关 键 词：南亚高压 西太副高 降水 特征指数 逐候变化 

分 类 号：P466[天文地球—大气科学及气象学]