摘要
采用多时间尺度方法,并假设纬向基本气流是正压的,在不引入剩余环流的情况下,推导出纬向基本气流局地变化与一种新形式EliassenPalm通量之间的关系,这种EliassenPalm通量关系在形式上比较简单,而且物理意义明确,适合诊断分析高空急流区内纬向基本气流的加速与减速。理论分析表明,正压纬向基本气流的局地变化由新形式EliassenPalm通量散度决定。作者利用该EliassenPalm通量关系对2002年12月一次寒潮过程中200hPa等压面上纬向基本气流的发展演变进行了诊断分析。诊断结果表明,在200hPa纬向基本气流急流区内,新形式EliassenPalm通量散度是影响纬向基本气流发展演变的重要因子,并且纬向基本气流的加速与减速主要是由新形式EliassenPalm通量中扰动动量的经向输送造成的。
The relation between the barotropic basic zonal flow and a new Eliassen\|Palm flux, which excludes the residual circulation, is examined by using the multi\|time scale method. The formulation of the relation is simple and has an explicit physical implication. The relation is applicable to diagnosing the acceleration and deceleration of the upper\|level basic zonal flow. It is shown on the theoretical grounds that for barotropic basic states, the tendency of the basic zonal momentum is mainly dominated by the new EP flux divergence. The relation is applied to diagnosing the evolution of the basic zonal flow at 200 hPa in a cold wave. The analysis reveals that the new EP flux divergence has an important influence on the evolution of basic zonal wind in the upper\|level jet stream region. The acceleration and deceleration of basic zonal flow mainly result from the meridional transportation of perturbation momentum.
出处
《大气科学》
CSCD
北大核心
2005年第3期409-416,共8页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金资助项目40405011
40333034
