Assessment of trends in an intergrated climate metric-Analysis of 200 mbar zonal wind for the period 1958-2021

TL;DR

This study analyzes long-term trends in 200 mbar zonal wind and polar jet position using reanalysis datasets from 1958 to 2021, finding no significant change in wind strength and minimal poleward shift of the jet stream.

Contribution

It provides a comprehensive assessment of climate-related wind trends over six decades using multiple reanalysis datasets, highlighting the lack of significant change.

Findings

No significant change in 200 mbar zonal wind strength.

Poleward movement of the Northern Hemisphere polar jet is not statistically significant.

No poleward shift of the Southern Hemisphere polar jet observed.

Abstract

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.