Extended Data Fig. 1: Characteristics of strong pIOD events.
From: Opposite response of strong and moderate positive Indian Ocean Dipole to global warming
a–c, SON SST anomalies (°C, color shading) and wind stress anomalies (N m−2, vectors) for the 1994, 1997, and 2006 strong pIOD event, respectively. The pattern is dominated by strong cooling in the equatorial eastern Indian Ocean. Strong equatorial easterly anomalies extend to the central-western Indian Ocean. The anomalies are referenced to the average over the 1982–2015 period. d–f, SON SST anomalies (in °C) relative to the SST threshold for tropical convection, defined as the SON SST average over 20°S to 20°N, for the 1994, 1997, and 2006 strong pIOD event, respectively. Areas with SST lower than the convection threshold have been masked; there is a large area of suppressed convection in the equatorial eastern Indian Ocean. g–i, Equatorial vertical potential temperature anomalies (in °C) over SON of 1994, 1997, and 2006, respectively. The equatorial vertical potential temperature is calculated as the average between 2.5°S to 2.5°N. Strong equatorial cooling is seen in the eastern Indian Ocean. Vertical potential temperature and wind stress data are from ORA-S5.
