Evaluating ENSO teleconnections using observations and CMIP5 models

• Published in: Theoretical and applied climatology Vol. 136; no. 3-4; pp. 1085 - 1098
• Main Authors: Roy, Indrani, Gagnon, Alexandre S., Siingh, Devendraa
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.05.2019; Springer; Springer Nature B.V
• Subjects: Analysis; Anomalies; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Bias; Climate change; Climate models; Climate science; Climatology; Computer simulation; Earth and Environmental Science; Earth Sciences; El Nino; El Nino phenomena; El Nino-Southern Oscillation event; Global climate; Global temperature changes; Ocean currents; Ocean models; Ocean temperature; Oceans; Original Paper; Regional climate models; Regional climates; Sea surface; Sea surface temperature; Simulation; Southern Hemisphere; Southern Oscillation; Surface temperature; Teleconnections; Tropical climate; Waste Water Technology; Water Management; Water Pollution Control; United States > US; Atlantic Ocean; Pacific Ocean
• ISSN: 0177-798X; 1434-4483
• DOI: 10.1007/s00704-018-2536-z

Bias correction of global and regional climate models is essential for credible climate change projections. This study examines the bias of the models of the Coupled Model Inter-comparison Project Phase 5 (CMIP5) in their simulation of the spatial pattern of sea surface temperature (SSTs) in different phases of the El Niño Southern Oscillation (ENSO) and their teleconnections—highlighting the strengths and weaknesses of the models in different oceanic sectors. The comparison between the model outputs and the observations focused on the following three features: (i) the typical horseshoe pattern seen in the Pacific Ocean during ENSO events with anomalies in SSTs opposite to the warm/cool tongue, (ii) different signature in the tropical Pacific Ocean from that of the North and tropical Atlantic Ocean, and (iii) spurious signature in the southern hemisphere beyond 45° S. Using these three cases, it was found that the model simulations poorly matched the observations, indicating that more attention is needed on the tropical/extratropical teleconnections associated with ENSO. More importantly, the observed SST coupling between the tropical Pacific Ocean and the Atlantic Ocean is missing in almost all models, and differentiating the models between high/low top did not improve the results. It also found that SSTs in the tropical Pacific Ocean are relatively well simulated when compared with observation. This work has improved our understanding of the simulation of ENSO and its teleconnections in the CMIP5 models and has raised awareness of the bias existing in the models, which requires further attention by climate modellers.