1980年干旱夏季黄河中下游地区水汽输送的基本特征  

TRANSPORT OF WATER VAPOR OVER NORTH CHINA DURING THE DROUGHT PERICD IN SUMMER OF 1980

作　　者：刘永强[1] 丁一汇[1] 李月洪[1] 

机构地区：[1]中国气象科学研究院

出　　处：《气象科学》1993年第1期65-73,共9页Journal of the Meteorological Sciences

基　　金：国家自然科学基金资助项目

摘　　要：根据欧洲中期天气预报中心(ECMWF)网格点资料计算了1980年夏季黄河中下游地区持续干旱期间水汽输送各物理量,以此分析了水汽输送的时间演变、垂直结构和水平分布等方面的特征。结果表明,与长江中下游地区(1980年出现了特大洪涝)比较,华北干旱区的运动学特征(散度和垂直运动)并未出现完全相反的情形,两地区之间的区别,除了程度上的差异外,主要是垂直结构明显不同。长江流域空气强上升区与水汽垂直强辐合区一致,而华北地区空气主要上升区的水汽垂直输送为辐散区或弱辐合区。因而尽管华北地区电存在着上升运动和层结不稳定,但由于水汽供应不足,降水仍明显偏少。分析还表明,水汽输送存在着与降水变化相对应的月时间尺度的低频振荡,准双周振荡也较明显。The features of water vapor transport, such as temporal evolution, vertical structure and spatial pattern, over North China during the prolonged drought in summer of 1980 have been analyzed through computation of water vapor flux based on the once dai1y ECMWF grid-point data at 12GMT. The result, indicate that i't is unlikely that the charaeteristics of the atmospheric mass divergence, ascending motion and stratification stability in North China were completely oppos ite to those in the Yangtze River Valley, where the heavy flood occurre in summer of 1980. There is the major differences that the Strong ascending motion and significant water vapor convergence overlap fairly well each other in the vertica' levels in the Yangtze River Valley, while the maximum ascending motion is accompanied by water vapor divergence or weak water vapor convergence in North China. This vert'ical structure in North China results in insufficient water vapor supply and, therefore, little condensation and precipitation in the middle and upper atmosphere were produced. Additionally, a mode of monthly-scale low frequency oscillation can be found in water vapor flux, which is in correspondence to the fluctuation period of rainfall.

关 键 词：水汽 黄河 干旱 中下游地区 

分 类 号：P426[天文地球—大气科学及气象学]