Investigation on Evolutive Laws of Geopotential Height of Two Poles and the Equator at 500hPa Geopotential Height Field

Abstract

AbstractGeopotential height data at 500hPa level in recent 50 years is used to investigate the evolutive laws of Antarctic, Equatorial and Arctic geopotential heights, zonal wind, and the correlation between one and another. Results show that Antarctic (Equatorial) geopotential height descends (ascends) evidently. Antarctic, Equatorial and Arctic geopotential heights have obvious features of interannual and interdecadal variability. Generally, there is an obvious negative correlation between Antarctic and Equatorial geopotential heights, while no obvious correlation between Arctic and Equatorial geopotential heights, or between Antarctic and Arctic geopotential heights. At special frequency of variation, Equatorial geopotential height oscillates behind Polar Regions, Arctic geopotential height oscillates behind Antarctic, then the initial region of climatic change is the South Pole. The trends and periodical variations of geopotential heights in these three regions should be responsible for significant ascending ability, interdecadal and interannual variability of zonal wind at mid‐high latitude. Further research results show that zonal wind indices ascend significantly and have an obvious feature of interdecadal oscillation in both hemispheres. Moreover, ascent amplitude of zonal wind index is larger in Southern Hemisphere (SH) than that in Northern Hemisphere (NH), while zonal wind index in SH oscillates behind Antarctic geopotential height.