气候变化领域集成服务门户(CCPortal): Understanding diverse model projections of future extreme el niño

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DOI	10.1175/JCLI-D-19-0969.1
	Understanding diverse model projections of future extreme el niño
	Stevenson S.; Wittenberg A.T.; Fasullo J.; Coats S.; Otto-Bliesner B.
发表日期	2021
ISSN	0894-8755
起始页码	449
结束页码	464
卷号	34 期号:2
英文摘要	The majority of future projections in the Coupled Model Intercomparison Project (CMIP5) show more frequent exceedances of the 5 mm day21 rainfall threshold in the eastern equatorial Pacific rainfall during El Niño, previously described in the literature as an increase in ''extreme El Niño events''; however, these exceedance frequencies vary widely across models, and in some projections actually decrease. Here we combine single-model large ensemble simulations with phase 5 of the Coupled Model Intercomparison Project (CMIP5) to diagnose the mechanisms for these differences. The sensitivity of precipitation to local SST anomalies increases consistently across CMIP-class models, tending to amplify extreme El Niño occurrence; however, changes to the magnitude of ENSO-related SST variability can drastically influence the results, indicating that understanding changes to SST variability remains imperative. Future El Niño rainfall intensifies most in models with 1) larger historical cold SST biases in the central equatorial Pacific, which inhibit future increases in local convective cloud shading, enabling more local warming; and 2) smaller historical warm SST biases in the far eastern equatorial Pacific, which enhance future reductions in stratus cloud, enabling more local warming. These competing mechanisms complicate efforts to determine whether CMIP5 models under- or overestimate the future impacts of climate change on El Niño rainfall and its global impacts. However, the relation between future projections and historical biases suggests the possibility of using observable metrics as ''emergent constraints'' on future extreme El Niño, and a proof of concept using SSTA variance, precipitation sensitivity to SST, and regional SST trends is presented. © 2020 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).
英文关键词	Climate change; Clouds; Rain; Competing mechanisms; Coupled Model Intercomparison Project; Eastern equatorial Pacific; Ensemble simulation; Equatorial Pacific; Exceedance frequencies; Future projections; Rainfall thresholds; Climate models; climate change; climate variation; El Nino-Southern Oscillation; ensemble forecasting; extreme event; future prospect; precipitation intensity; sea surface temperature; weather forecasting; Pacific Ocean; Pacific Ocean (Equatorial)
语种	英语
来源期刊	Journal of Climate
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/170946
作者单位	Bren School of Environmental Sciences and Management, University of California at Santa Barbara, Santa Barbara, CA, United States; NOAA Geophysical Fluid Dynamics Laboratory, Princeton, NJ, United States; Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO, United States; Department of Earth Sciences, University of Hawai'i at Manoa, Honolulu, HI, United States
推荐引用方式 GB/T 7714	Stevenson S.,Wittenberg A.T.,Fasullo J.,et al. Understanding diverse model projections of future extreme el niño[J],2021,34(2).
APA	Stevenson S.,Wittenberg A.T.,Fasullo J.,Coats S.,&Otto-Bliesner B..(2021).Understanding diverse model projections of future extreme el niño.Journal of Climate,34(2).
MLA	Stevenson S.,et al."Understanding diverse model projections of future extreme el niño".Journal of Climate 34.2(2021).