Portfolio of the cold season. Correlation between the weights of EOM3 and the upwelling index. Left: lagged correlations between EOM3 weights in March and the upwelling index 6 months earlier. Right: boxplot of upwelling indices for all months except September and September (i.e. 6 months before March). In red the values for the nine years when a survey was performed in March with concomitant upwelling observations.