副热带高压季节性北跳的诊断研究

A DIAGNOSTIIC RESEARCH OF THE SEASONAL NORTHWARD BEATING OF THE SUBTROPICAL HIGH

关键词:  副热带高压  季节性北跳  西传  源汇  CEOF分析  低频振荡

Key words:  The subtropic high  Seasonal northward beating  Origin and sink  Analysis of CEOF method  Low-frequency oscillliation

摘要:

用CEOF、功率谱、带通滤波等方法和1988年、1991年5-7月逐日2.5°×2.5°500hPa位势高度场资料对北半球副热带高压季节性北跳进行了诊断研究。得出：副热带高压季节性北跳及西传是全球现象；副高发生季节性跳动的源主要位于阿拉伯海地区和中太平洋地区,汇主要位于东太平洋地区；副高的季节性跳动主要是扰动场的作用；低频振荡在副高的季节性跳动及西传中起举足轻重的作用,各年副高季节性跳动的差异是扰源和扰源激发出的低频波不同所致。

Abstract:

Some diagnostic methods of CEOF, power spectrum and bandpass filter wave were applied in this paper to analyse the seasonal northward beating of the subtropic high with the daily date of the 500hPa geopotential height field divided by the grid spacing of 2.5°x 2.5°. It was concluded that it is a global phenomenon that the subtropical high seasonally beats northward and this beating propagates westward; the origin of the beating caused by the disturbance field mainly lies in the Arabian Sea and the middle Pacific Ocean area and the sink area is the east Pacific Ocean; During the seasonal beating of the subtropic high and the westward propagation of this beating low-frequency oscilliation act as a very important role. The difference of the subtropic high's beating per year depends on the change of disturbance origin and the low-frequency wave it excites.