气候变化领域集成服务门户(CCPortal): No Emergence of Deep Convection in the Arctic Ocean Across CMIP6 Models

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DOI	10.1029/2023GL106499
	No Emergence of Deep Convection in the Arctic Ocean Across CMIP6 Models
	Heuze, Celine; Liu, Hailong
发表日期	2024
ISSN	0094-8276
EISSN	1944-8007
起始页码	51
结束页码	4
卷号	51 期号:4
英文摘要	As sea ice disappears, the emergence of open ocean deep convection in the Arctic, which would enhance ice loss, has been suggested. Here, using 36 state-of-the-art climate models and up to 50 ensemble members per model, we show that Arctic deep convection is rare under the strongest warming scenario. Only five models have convection by 2100, while 11 have had convection by the middle of the run. For all, the deepest mixed layers are in the eastern Eurasian basin. When that region undergoes a salinification and increasing wind speeds, the models convect; yet most models are freshening. The models that do not convect have the strongest halocline and most stable sea ice, but those that lose their ice earliest -because of their strongly warming Atlantic Water- do not have a persistent deep convection: it shuts down mid-century. Halocline and Atlantic Water changes urgently need to be better constrained in models. Both observations and modeling simulations suggest that deep vertical mixing (or deep convection) in winter may become the new normal in the Arctic as sea ice disappears, which further accelerates that disappearance. These simulations are often done using only one model, so here we used all models available that participated in the Climate Model Intercomparison Project Phase 6 (CMIP6), for the strongest warming scenario. We show that after removing those that are already inaccurate in the present, and even with a restrictive threshold, most models have no deep convection in the Arctic, or extremely rarely. Only five still had deep convection by the time the run finishes in 2100. We found that deep convection regions and periods are associated with a saltier, windier surface, while the rest of the Arctic and/or run freshens. The subsurface properties were crucial too: a deep halocline, that is, strongly stratified model, leads to less ice loss and no deep convection. In contrast, models with a shallow halocline and strongly warming Atlantic Water lose their ice and convect earliest, although it does not persist. As water mass properties are poorly represented in CMIP6 models, these need improving to better constrain Arctic deep convection and sea ice projections. Oceanic deep convection does not emerge and persist in the Arctic in the majority of Climate Model Intercomparison Project Phase 6 models, despite a drop in the Nordic Seas Arctic deep convection occurs only when both surface salinity and winds are increasing, year round, yet most models are freshening A deep halocline and stable ice cover hinder deep convection, while early ice loss due to warmer Atlantific water can also stop it rapidly
英文关键词	Arctic Ocean; climate models; mixing; stratification; climate change
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:001167975800001
来源期刊	GEOPHYSICAL RESEARCH LETTERS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/306225
作者单位	University of Gothenburg; Yunnan University
推荐引用方式 GB/T 7714	Heuze, Celine,Liu, Hailong. No Emergence of Deep Convection in the Arctic Ocean Across CMIP6 Models[J],2024,51(4).
APA	Heuze, Celine,&Liu, Hailong.(2024).No Emergence of Deep Convection in the Arctic Ocean Across CMIP6 Models.GEOPHYSICAL RESEARCH LETTERS,51(4).
MLA	Heuze, Celine,et al."No Emergence of Deep Convection in the Arctic Ocean Across CMIP6 Models".GEOPHYSICAL RESEARCH LETTERS 51.4(2024).