Assessment of trends in an integrated climate metric—analysis of 200 mbar zonal wind for the period 1958–2021

Abstract

AbstractUsing two reanalysis datasets on latitude bands of nearly equal area, we analyze the trend of 200 mbar zonal wind anomalies for the period 1958–2021 as well as annual-mean latitude of the zonal mean jet stream. We do not find much change of 200 mbar zonal wind in both two datasets although the increasing trend over the high latitude bands from 45 to 61°S for both datasets, and the decreasing trend in 0–5°N and 0–10°S for ERA5 are significant with small magnitudes. In addition, the polar jet core moves poleward in the Northern Hemisphere, but the movement is not statistically significant, while no poleward shift at all has occurred in the Southern Hemisphere. This work provides us a way to look for the long-term changes and variability in atmospheric circulation.