The southerly water vapor can progress to 50 n near north - east in china - , the southeasterly water vapor from south side of the west pacific subtropical high and north side of the monsoon trough can march westward to 100 e near south - east part of gansu in summer 东亚夏季偏南风水汽输送所能到达的北界为50 n附近的东北北部。西太平洋副高南侧、亚洲季风槽北侧的东南风水汽输送在夏季可向西扩展到甘肃东南部地区( 100 e附近) 。
These make west - pacific subtropical height strengthen and extend westward and blocking form and develop in mid - high latitude , while its above west wind drift zone decreases . and around 1976 , 500hpa anomaly field of winter and summer also changes 其中变化比较显著的是贝加尔湖附近和副高，都是76年后增强，这有利于低纬副高的加强西伸和中高纬阻塞的形成和发展；并且在76年前后，厄尔尼诺和拉尼娜年冬、夏季500hpa距平场也有一定的差异。
Results show that subtropical high in june 1998 is more intensive and westerly and than normal , leading to the floods in yangtze river valley . vertical diabatic heating has stronger impacts on the variation of intensity and location of western pacific subtropical high 结果表明： 1998年6 - 7月西太平洋副高较常年同期偏强偏西，从而导致了我国长江流域持续暴雨洪涝天气的发生；副热带地区的非绝热加热对副高的强度和位置的变化有极其重要影响。
Sea - ice of hudson bay in key time interval has negative relationship with index of asian summer monsoon , positive relationship with the western subtropical ridge in west pacific in august , and negative relationship with the intensity of the west pacific subtropical in august 同时该海区海冰与亚洲季风呈负相关，与西太平洋副热带高压的强度也呈负相关，而与副高西伸脊点呈正相关。这说明哈得孙湾海冰是通过这两个系统来影响华北夏季降水的。
May , the abnormal precipitation is mostly effected by the east - westward location difference of the subtropical high pressure of the west pacific and the trough of east asia , while the cross equatorial flow streams at low level near 105 e almost have no effect to it 五一期间两区降水异常主要受西太平洋副高和东亚槽东西位置差异及强弱的影响， 105 “ e附近越赤道气流对两区降水影响都不是很大。十一期间两区降水异常主要受西太平洋副高南北位置差异及强弱的影响。
( 2 ) another interesting phenomenon is founded that the center of south asia high in the upper level of troposphere is stabile and nearly motionless during the processes of the westward extension of western pacific subtropical high , but its eastern ridge strengthens and extends eastward remarkably because of the anticyclone moves westward over the southeast japan , which may lead to the westward extension of subtropical high in the middle level of troposphere . ( 3 ) in the low level of troposphere , the north australia cold air activity plays an important role on the westward extension of subtropical high ( 2 )本文在研究副高西伸过程中指出，高层200hpa上日本东南部的高压并入南亚高压，导致南亚高压脊的增强发展，对低层500hpa上副高的加强、西伸可能起到引导的作用；同时，对流层低层850hpa上孟加拉湾槽在副高西伸过程中加深，并在西伸脊点到达最西点的前4天强度达到最强，这为预报西太平洋副高的活动提供了参考。
Based on this conclusion , the possibly formation mechanism of the double sh ridges is discussed . the results show that the formation process of double sh ridge is discrepant for the different style . the first style occurs as a result of the northward movement , the through - get and consolidation of the equatorial buffer band with the wpsh , and the second one is due to the strength , western extension , and then through - get and consolidation of the mid - pacific with the equatorial buffer band 在此基础上，分析了副高双脊线的形成原因，结果表明，不同类型的双脊线，其形成过程不同:第一类双脊线是赤道缓冲带(赤道反气旋)北上与副高打通合并的结果，而第二类双脊线却是由于中太平洋反气旋加强西伸，与赤道缓冲带打通合并而形成的。
The main relative systems of heavy - hard rainfall in northeast plateau are western pacific subtropical high , south asia high , low latitude systems , upper level jet ( ulj ) , low level greater wind speed axes , westerly trough and plateau trough , low level vortex , cold frontal , occluded front in qinghai lake , mesoscale low pressure , heat low - pressure in qinghai , shear line and convergence line , mesoscale cloud cluster , etc . the west subsidiary model of south asia high is the main circulation type of heavy - hard rainfall in this area 3 、西太平洋副高、南亚高压、低纬系统、高空急流、低空大风速轴；西风槽和高原槽、低涡、冷锋、青海湖锢囚锋以及中尺度低压、青海热低压、切变线与辐合线、中尺度云团等系统是高原东北部地区大到暴雨的主要相关系统。 100hpa上的南亚高压中心强度加强，位置东西摆动预示高原地区将有降水产生，中心强度减弱，降水过程结束。南亚高压西部副型是高原东北部地区大到暴雨的主要流型。
2 . rebuilding of the double sh ridges based on the case of double ridges during the breaking interval of plum - season rainfall in the summer of 1998 , it is indicated that the sh ridge would remarkably locate much more southward than its normal position after the phenomenon of double sh ridge is over . furthermore , this southward migration of sh ridge is not sudden but results from the southward rebuilding of the double sh ridges , that is , the northern ( original ) ridge gets enfeebled and disappeared , in contrast , the southern counterpart becomes intensified enough and steadily persists ( 2 )副高脊线的“重建”根据98年夏季梅雨间歇期副高双脊线个例，指出双脊线现象结束后，副高脊线会出现显著偏南，且这种偏南不是突发性的，而是副高脊线在南侧“重建”的结果，即副高北侧脊线减弱消失，南侧脊线发展维持。
Abstract : monthly rainfall data from 1951 to 1995 for june , july and august in 13 meteorological stations of the north china were used for accounting z index and discussing serious flood and drought featureas in these months . serious flood mainly happened in july and august , and sevious drought mainly happened in august . there were more flood in 1950 ' s to 1960 ' s and more drought since 1970 ' s in the north china . meanwhile , the deeper trough which covered the regions from the ural mts . to the balkhash lake play an important role in serious rainstom in rainy season in the north china . there often happened serious flood ( drought ) when the northwester pacific subtropical high was by west and north ( east and south ) , and the sea surface temperature in the equatorial central and eastern pacific was mainly in dropping ( raising ) stage 文摘:利用华北平原地区的13个站点, 45年（ 1951 1995 )的降水资料,对夏季4个时段（ 6月、 7月、 8月、 6 8月）进行了z指数计算,确定了该地区各个时段的严重涝年和严重旱年.发现华北地区雨季的严重洪涝主要集中在7 , 8月,严重干旱则主要发生在8月,并可明显看出由50 60年代的多水期向70年代中期以后的少水期的转变,另外,乌拉尔山到巴尔喀什湖附近的低压槽加深和西北太平洋副热带高压的北抬,对华北地区雨季持续性暴雨的产生起着决定性的作用.严重洪涝年的夏季（ 6 8月） ,西北太平洋副热带高压偏西、偏北,赤道东太平洋海温多处于下降阶段;严重干旱年西北太平洋副高偏东、偏南,赤道东太平洋海温则处于上升阶段
