CMIP6 model evaluation for sea surface height responses to ENSO

El Niño-Southern Oscillation (ENSO) exhibits a substantial impact on sea surface height (SSH), and some climate models are significantly biased in reproducing the observed ENSO impact on SSH. This study aims to assess the performance of 26 Coupled Model Intercomparison Project Phase 6 (CMIP6) models for global SSH response to ENSO using their historical simulations from 1958 to 2014 during December‒February (DJF). The observation data for SSH and sea surface temperature (SST) are derived from Ocean Reanalysis System 5 (ORAS5). The fidelity of models is evaluated based on skill metric parameters such as root mean square error, interannual variability skill score, and M-Score. In CMIP6 models, El Niño plays a dominant role to simulate enhanced SSH across eastern Pacific Ocean (Region I) and southwest tropical Indian Ocean (Region III). In contrast, El Niño induces cooler SSTs over the region bounded between 100°E–133°E, 5°S–20°N (Region II), which is further associated with reduced SSH. The inter-model relationship of ENSO amplitude with the area mean regression coefficient for SSH and SST is investigated for these three hotspot regions. Overall, models with stronger ENSO amplitude simulate higher values of SSH and SST over Region I, III, and weaker amplitude over Region II.