月尺度西太平洋副热带高压指数的重建与应用  

Reconstruction and Application of the Monthly Western Pacific Subtropical High Indices

作　　者：刘芸芸[1] 李维京[1] 艾(孑兑)秀[1] 李清泉[1] 

机构地区：[1]国家气候中心,北京100081

出　　处：《应用气象学报》2012年第4期414-423,共10页Journal of Applied Meteorological Science

基　　金：国家重点基础研究发展计划(2010CB950501);国家重大科学研究计划(2012CB955203);国家自然科学基金项目(41005037);国家科技支撑计划(2009BAC51B05;2007BAC29B04)

摘　　要：针对目前国家气候中心业务监测中使用的月时间尺度西太平洋副热带高压指数存在的问题,利用NCEP/NCAR月平均再分析资料,对西太平洋副热带高压面积指数、强度指数、脊线指数和西伸脊点4种指数重新进行定义和计算,重建了1951—2010年逐月历史时间序列。面积指数、强度指数采用真实的面积和体积进行定义和计算,脊线指数则同时利用500 hPa高度场和纬向风切变线进行定义,且不仅仅局限于588 dagpm等值线,充分考虑了西太平洋副热带地区高压系统对我国夏季降水的影响作用。选取其中两个相对独立的指数——脊线指数与西伸脊点,通过对这两个指数的9种组合类型的构建,最大程度上涵盖了我国东部夏季降水各种雨型的分布特征。In order to solve the problems of the monthly Western Pacific Subtropical High （WPSH） indices used in National Climate Center（NCC） monitoring service, a series of the monthly WPSH indices, including the area index, intensity index, ridge line index and western boundary index, are redefined and reconstructed, on the basis of the monthly NCEP/NCAR reanalysis datasets from 1951 to 2010. The reconstructed area mclex is aennea Dy tile contour over western Pacific, while the intensity index is the ＂volume＂ of the WPSH over 588 dagpm. The reconstructed western boundary index is defined as the minimal longitude degree of the 588 dagpm contour in the region between 90°E and 180°.When 588 dagpm contour disappears in some month, it is substituted by the maximum of this index in this month during 1951 to 2010. The definition of the reconstructed ridge line index has more adjustment. It is defined by the latitude position of the isoline where 500 hPa zonal wind u=0 and δu/δy〉0 surrounded by 588 dagpm contour. When there is no 588 dagpm contour, the 584 dagpm contour is just considered in the definition. If even no 584 dagpm contour exists in some month, it is substituted by the minimum of this index in this month during 1951 to 2010. Both the 500 hPa geopotential height and 500 hPa zonal wind shear line are considered in the reconstructed ridge line index, and no more restricted by 588 dagpm contour, which takes full consideration of the impact of the WPSH system on the summer precipitation in East China. The reconstructed WPSH indices have monthly change, and overcoming the defect enabled describing objectively characteristics of the WPSH＇s of the excessive dependence of the WPSH indices using in NCC service on the data resolution. The significant correlation of the reconstructed ridge line index and the summer precipitation over the Yangtze River also confirms its rationality and objectivity. Finally, two kinds of relatively independent WPSH indices, the ridge line index and western ridge point index,

关 键 词：西太平洋副热带高压 面积指数 强度指数 脊线指数 西伸脊点 

分 类 号：P732.1[天文地球—海洋科学]