Annex IV Figure 10

Figure AIV.10 | (a) The spatio-temporal properties of the Madden–Julian Oscillation (MJO). Daily composites of outgoing longwave radiation (OLR, W m–2, shaded) anomalies and stream-function anomalies at 300 hPa (STF, contours every 0.5 x 106 m2 s–1) for the eight MJO phases in boreal winter (1 December to 31 March) based on NOAA interpolated satellite products and NCEP–NCAR reanalysis over 1979–2019, respectively. Greenish (brownish) colours indicate enhanced (reduced) convective activity associated with wet (dry) conditions. Solid (dashed) contours show for positive (negative) STF anomalies which stand for anomalous anticyclonic circulation in the Northern (Southern) Hemisphere. (b) Phase diagram of the MJO constructed from the two leading principal components drawn from empirical orthogonal decomposition of combined wind at 300 hPa + OLR fields following Wheeler and Hendon (2004) for winter 2007–2008 chosen as an example of active MJO years. (c) Schematic representation of MJO-related tropical–Northern Hemisphere interactions and teleconnections inferred from observational and numerical studies (adapted from Stan et al., 2017). Because the interactions and teleconnections of the Southern Hemisphere are not as well understood except for the Southern Annular Mode, they are not included in the current schematic.