  Using the ERA5 and JRA-55 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 polar jet stream. We
find basically no change of 200 mbar zonal wind in either the JRA-55 or ERA5
dataset. 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.
