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DOI | 10.1007/s00382-020-05152-2 |
Walker circulation controls ENSO atmospheric feedbacks in uncoupled and coupled climate model simulations | |
Bayr T.; Dommenget D.; Latif M. | |
发表日期 | 2020 |
ISSN | 0930-7575 |
起始页码 | 2831 |
结束页码 | 2846 |
卷号 | 54 |
英文摘要 | Many climate models strongly underestimate the two most important atmospheric feedbacks operating in El Niño/Southern Oscillation (ENSO), the positive (amplifying) zonal surface wind feedback and negative (damping) surface-heat flux feedback (hereafter ENSO atmospheric feedbacks, EAF). This hampers a realistic representation of ENSO dynamics in these models. Here we show that the atmospheric components of climate models participating in the 5th phase of the Coupled Model Intercomparison Project (CMIP5) when forced by observed sea surface temperatures (SST), already underestimate EAF on average by 23%, but less than their coupled counterparts (on average by 54%). There is a pronounced tendency of atmosphere models to simulate stronger EAF, when they exhibit a stronger mean deep convection and enhanced cloud cover over the western equatorial Pacific (WEP), indicative of a stronger rising branch of the Pacific Walker Circulation (PWC). Further, differences in the mean deep convection over the WEP between the coupled and uncoupled models explain a large part of the differences in EAF, with the deep convection in the coupled models strongly depending on the equatorial Pacific SST bias. Experiments with a single atmosphere model support the relation between the equatorial Pacific atmospheric mean state, the SST bias and the EAF. An implemented cold SST bias in the observed SST forcing weakens deep convection and reduces cloud cover in the rising branch of the PWC, causing weaker EAF. A warm SST bias has the opposite effect. Our results elucidate how biases in the mean state of the PWC and equatorial SST hamper a realistic simulation of the EAF. © 2020, The Author(s). |
语种 | 英语 |
scopus关键词 | atmospheric convection; atmospheric modeling; climate modeling; cloud cover; CMIP; computer simulation; El Nino-Southern Oscillation; heat flux; sea surface temperature; surface wind; Walker circulation; zonal wind; Pacific Ocean; Pacific Ocean (Equatorial); Pomatiopsis californica |
来源期刊 | Climate Dynamics |
文献类型 | 期刊论文 |
条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/145551 |
作者单位 | GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, Kiel, 24105, Germany; School of Mathematical Sciences, Monash University, Clayton, VIC, Australia; Cluster of Excellence “The Future Ocean”, University of Kiel, Kiel, 24105, Germany |
推荐引用方式 GB/T 7714 | Bayr T.,Dommenget D.,Latif M.. Walker circulation controls ENSO atmospheric feedbacks in uncoupled and coupled climate model simulations[J],2020,54. |
APA | Bayr T.,Dommenget D.,&Latif M..(2020).Walker circulation controls ENSO atmospheric feedbacks in uncoupled and coupled climate model simulations.Climate Dynamics,54. |
MLA | Bayr T.,et al."Walker circulation controls ENSO atmospheric feedbacks in uncoupled and coupled climate model simulations".Climate Dynamics 54(2020). |
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