Fig. 6: Composite 500 hPa geopotential height anomalies for different vortex center shifts. | npj Climate and Atmospheric Science

Fig. 6: Composite 500 hPa geopotential height anomalies for different vortex center shifts.

From: Can stratospheric nudging improve surface predictability? Insights from the 2019 Southern Hemisphere sudden stratospheric warming

Fig. 6: Composite 500 hPa geopotential height anomalies for different vortex center shifts.The alternative text for this image may have been generated using AI.

a1–c1 Composite 500 hPa geopotential height anomalies averaged from 18 October to 14 November, for westward-shifted vortex centers (west of 30°W) for control, free, and nudged runs, respectively, using multimodel multi-ensemble members (totaling 352, with CMA excluded). Dots mark the composite anomalies relative to the simultaneous ERA5 climatology at the 95% confidence level according to a one-sample t-test. a2–c2 As in (a1–c1), but for eastward-shifted vortex centers (east of 0°E). a3–c3 Composite difference between westward-shifted vortex centers. Dots mark the difference between two composite means at the 95% confidence level according to a two-sample t-test. N represents the sample size in each composite. The Meridional Ridge-Trough Index (MRTI) is calculated as the height difference between two boxes (20°S–40°S, 120°E–180°; 40°S–60°S, 120°E–180°).

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