Simulated mean state changes in SST and Pacific equatorial subsurface temperature and tropical upper ocean circulation. Comparisons between (left panels) the observed trends and (right panels) the mean state changes simulated by POAMA (wClim-pClim) for OND. (a,b) SSTs, (c,d) equatorial Pacific temperatures in the upper 300 m, (e,f) vertical velocities at the bottom of the mixed layer (45 m) (colour shading) overlayed with the horizontal velocities of currents averaged in the mixed layer (vectors). SSTs averaged over the red and blue boxes in (a) and (b) were used to estimate the zonal SST gradients40. The colour shading interval is 0.4 °C beginning at +/−0.2 °C for temperatures in (a–d) and 3.0*10−6 and 2.0*10−6 m/s for vertical velocity in (e) and (f), respectively. The size of the reference vector is 0.6 and 0.4 m/s in (e) and (f), respectively. Statistical significance at the 5% level is stippled in (a–d), and in (e) and (f) the zonal and vertical velocity trends and changes significant at the 5% level are displayed (see Methods for details of statistical significance tests).