Fig. 7: Tropical convection, Rossby wave propagation and Amundsen Sea Low - Weddell Sea High couplet development.
a Daily anomalies in outgoing longwave radiation (OLR; shaded) and 200-hPa divergent wind (vectors, m s−1, with divergent wind speeds <3 ms-1 and poleward of 45°S omitted), and daily mean 200-hPa Rossby wave source (magenta contours for positive (anticyclonic vorticity forcing) RWS and black dashed contours for negative (cyclonic vorticity forcing) RWS, interval is 6 × 10–9 s−2 from ±30 × 10–9 s−2 and the zero contour is omitted, see “Methods”) for 4 February 2022. b Daily anomalies in 500-hPa geopotential height (Z500, gpm; shaded and contoured) and 200-hPa stationary wave flux (vectors, m2 s−2, with wave fluxes containing zonal components <15 m2 s−2 (easterly or weak westerly) or meridional components >20 m2 s−2 (strongly southerly) omitted; see “Methods”) for 4 February 2022. c–h Same as (a, b) but for (c, d) 5 February, (e, f) 6 February, and (g, h) 7 February 2022. All anomalies are based on the 1979–2021 long-term mean calculated over the 5-day pentad average centered on each day. Atmospheric data are from ERA5 and OLR data are based on NOAA’s interpolated OLR dataset (see “Methods”).
