Underestimated responses of Walker circulation to ENSO-related SST anomaly in atmospheric and coupled models

Geoscience Letters

Nathaniel C. Johnson¹  Chueh-Hsin Chang²  Jiang Zhu³  Chentao Song³  Xin-Yue Wang³  Yi Zhou³  Hailong Liu³  Xichen Li³  Meijiao Xin³  Yadi Li³ 

[1] Atmospheric Oceanic Sciences Program, Princeton University;Center for Climate Change Prediction Research, Ewha Womans University;Institute of Atmospheric Physics, Chinese Academy of Sciences;

关键词: Pacific Walker circulation;    ENSO;    AMIP5/6 and CMIP5/6 models;    Atmosphere–ocean interaction;    Model bias;   

DOI  :  10.1186/s40562-021-00186-8

来源: DOAJ

【 摘 要 】

Abstract The Pacific Walker circulation (WC) is a major component of the global climate system. It connects the Pacific sea surface temperature (SST) variability to the climate variabilities from the other ocean basins to the mid- and high latitudes. Previous studies indicated that the ENSO-related atmospheric feedback, in particular, the surface wind response is largely underestimated in AMIP and CMIP models. In this study, we further investigate the responses in the WC stream function and the sea level pressure (SLP) to the ENSO-related SST variability by comparing the responses in 45 AMIP and 63 CMIP models and six reanalysis datasets. We reveal a diversity in the performances of simulated SLP and WC between different models. While the SLP responses to the El Niño-related SST variability are well simulated in most of the atmospheric and coupled models, the WC stream function responses are largely underestimated in most of these models. The WC responses in the AMIP5/6 models capture ~ 75% of those in the reanalysis, whereas the CMIP5/6 models capture ~ 58% of the responses. Further analysis indicates that these underestimated circulation responses could be partially attributed to the biases in the precipitation scheme in both the atmospheric and coupled models, as well as the biases in the simulated ENSO-related SST patterns in the coupled models. One should pay special attention to these biases when studying the WC or the tropical atmosphere–ocean interactions using numerical models.

【 授权许可】

Unknown