Fig. 6: Evolution characteristics of wind field during two QBO disruptions (MERRA2 data).

Differences in the zonal-mean zonal wind between QBO disruption and climatology for 2015/16D (a–d) and 2019/20D (e–h) in four periods. (a, e) correspond to the period before the eastward-moving wave (Fig. 2c–d), and the rest of the periods correspond to T1-T6. The blue stars represent the location of the 38 hPa pressure level at 17.5°N (17.5°S). The red contours represent the zonal mean zonal wind after the time average in the corresponding period, and the shadings represent the wind speed difference with the climatology. The black dots indicate where the results are statistically significant (one standard deviation above the climatology).