太平洋热带地区气压的中期振动及其低层大型环流演变特征与台风“群”的关系

众所周知,广大低纬地区气压梯度微弱,气压日变化往往掩盖了某些更有意义的气压变化.地面天气图上常规的等压线分析任意性强.因此,在低纬天气分析中大都以流线为主.尽管如此,我们认为低纬气压资料也不能忽视.事实上,近年来已在非洲一些地区利用经过处理的气压记录分析热带天气,并在降水预报中作了初步尝试1].我们分析了1973-1979年全年热带大范围地面图、700mb图及有关卫星云图,研究了低纬气压的演变特征及其相应的环流变化.利用1974-1977年资料,对比南北两半球夏季低纬环流的异同,以1978年8月-1979年7月全年资料为例,给出全年热带地区气压中期振动的事实.

THE MEDIUM-RANGE OSCILLATION IN PRESSURE OVER THE PACIFIC TROPICAL REGION AND THE RELATIONSHIP BETWEEN LARGE-SCALE CIRCULATION AND GENERATING GROUPS OF TYPHOONS

The synoptic map of the surface and 700mb and satellite cloud pictures over the Pacific tropical region during 1973-1978 is studied in this paper. In this region, there is a medium range oscinanon in pressure similar to that over the middle-high latitude region for a period of about 4-6 weeks.This paper discussis the mediums-range oscillation with large-scale circulation and generation of group of typhoons, thus providing a method of forecast medium-range of typhoons in this region. finally we use a curve of change in pressure index to demonstrate this cycle, in order that the cycle can be seen clearly.