资源环境科技发展态势分析平台

The mechanisms behind the maintenance and variability of the Southern Hemisphere (SH) winter subtropical jet are examined, in comparison with those of the Northern Hemisphere (NH) jet. It is found that atmospheric waves play an important role in setting the climatological jet position and controlling its variability on various time scales. The mechanisms of maintenance and variability are broadly very similar in the two hemispheres, but low-frequency transient waves and synoptic waves play major roles in maintaining the climatological jet and in forcing monthly time scale variability, respectively, in the SH, whereas stationary waves are dominant for both roles in the NH. Accordingly, the 1 month lagged autocorrelation for the subtropical jet zonal wind is found to be much smaller in the SH than in the NH.