The anomalous non - uniform heating induces anomalous cyclonic vorticity in south china , areas to the south of the yangtse and its mid - lower valleys , but anomalous anticyclonic vorticity in the indo - china peninsula and south china sea areas lead to the more southward position of wpsh than the mean 这种异常的非均匀加热状况导致我国华南、江南、长江中下游地区呈现异常气旋性涡度制造，而中南半岛大部和南海地区为异常反气旋性涡度制造，使得1998年6月副高位置异常偏南。
In 1999 , the dipole existed in between the okhotsk high and the depression in the north of northeast china , thus the okhotsk high became active and maintained , the subh was located to an area quite further south than usual . the high persisted in the east region of nw china , the cold air flowed to the mid - lower reaches of the yangtze river along the high . in the east region of nw china , air steam under troposphere was strong sinking motion , and formatted the negative vorticity region , the vapour flux divergence was divgence . lt was apparently that the rain could n ' t occur in the eastern portin of nw china . in 2000 year , okhotsk high was very weak or did n ' t exist in , there was high in the east asia - japan , the subh is located to an area further north than usual . in the east region of nw china , the trough maintained , air stream under troposphere was strong ascending motion , the cycolonic circulation was prevailing , the vapour flux divergence was intensive convergences the rain easy happened in the east areas of northwest china 4多梅雨1999年鄂霍茨克海阻塞高压与我国东北北部低压形成偶极子，使得阻塞高压稳定少动，西太副高位置偏南，西北地区东部持续受高压控制，冷空气沿此高压流经长江中下游地区上空；在西北地区东部对流层中下层气流下沉运动较强，呈反气旋涡度，水汽通量散度辐散，不利于西北地区东部降水。空梅雨2000年相反，鄂霍茨克海高压减弱甚至不存在，东亚-日本为高压，西太副高位置偏西偏北，西北地区东部处于西风槽中，对流层中下层气流上升运动增强，盛行低压环流，水汽通量散度强烈辐合，有利于降水生成。
Analysis shows that when summer precipitation in north china is richer ( less ) , tropical east pacific ssta is colder ( warmer ) phase , and slp and 500hpa geo - potential height are negative ( positive ) anomaly over the asia , west pacific sub - high is northerner ( southerner ) , and block high in mid - highs latitude happens less ( more ) than normal , east monsoon is stronger ( weaker ) 分析表明华北夏季多(少)雨期，赤道中东太平洋ssta处于冷(暖)位相，在非洲大陆上slp利500hpa位势高度均为负(正)异常，西北太平洋副高位置偏北(南) ，中纬度阻塞高压发生频率较低(高) ，东亚夏季风偏强(弱) 。
