Assessment of ERA-Interim-driven RCM simulations in reproducing the link between ENSO and Climate Extreme Indices

The link between ENSO and precipitation patterns has been extensively studied. However, whether RCM simulations and their driving data can reproduce this link remains unclear. This study aims to evaluate the ability of ERA-Interim-driven RCM simulations to replicate the spatial patterns of the temporal correlation between ENSO and Climate Extreme Indices (CEI) -CDD, CWD, Rx1, and Rx5- over Mexico from 1980 to 2012. First, the accuracy of ENSO reproduction with ERA-Interim was assessed. Second, RCM simulations’ performance in reproducing the CEIs was evaluated. Finally, the replication of the spatial pattern of temporal correlation between ENSO and CEIs and its statistical significance were analyzed. The findings reveal that ERA-Interim can accurately reproduce the ENSO index. Both ERA-Interim and the simulations are capable of replicating CEIs spatial representation throughout the study period, although they tend to overestimate the maximum and minimum values. Both ERA-Interim and the simulations reproduce the observed humidity conditions in Mexico, characterized by a dry north and wet south. Among the CRCM5 simulations, the 0.22 resolution shows the best agreement with the CDD and CWD indices, while the 0.44 resolution aligns best with the Rx1 and Rx5 indices. Moreover, ERA-Interim and RCA4 simulation show better agreement in reproducing the correlation of ENSO calculated with ERA-Interim and CDD, while the CRCM5 0.22 simulation shows this for CWD. The seasonal CEIs correlation with ENSO was best represented by both CRCM5 simulations for summer in the CDD and CWD indices, whereas just the RegCM4-7 simulation was unable to reproduce this link in winter.