Evaluating ENSO teleconnections using observations and CMIP5 models

Abstract

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.

Analysis of ENSO simulation biases in FIO-ESM version 1.0

“…(Qiao et al 2013;Liu et al 2014;Song et al 2014) by incorporating the non-breaking surface wave vertical mixing (hereafter wave-induced mixing) into the model. In particularly, the model exhibits good performance in terms of ENSO diversity (Matveeva et al 2018), spatial distributions of SST peaks during El Niño events (Graham et al 2017), relationships between ENSO and the Northern Hemisphere polar region (Roy et al 2019), and ENSO predictions (Song et al 2015). However, it still suffers from similar ENSO simulation biases similar to those of other CMIP5 models (Bellenger et al 2014;Taschetto et al 2014;Yun et al 2016).…”

The role of natural factors (part 1): addressing on mechanism of different types of ENSO, related teleconnections and solar influence

“…The ENSO through teleconnection can affect various regions around the world (Roy et al 2018). It also influences seasonal precipitation in several places, among which the Indian Summer Monsoon (ISM) is an important one.…”

ENSO teleconnections to the Indian summer monsoon under changing climate

“…It is noteworthy that in terms of tropical Pacific SST pattern, CMIP5 models can separate the canonical and Modoki ENSO features reasonably well (Taschetto, ; Roy et al , ; ). All models can show some evidence of both modes though some models are better than others.…”