气候变化领域集成服务门户(CCPortal): Bistability of the Filchner-Ronne Ice Shelf Cavity Circulation and Basal Melt

CCPortal

DOI	10.1029/2019JC015848
	Bistability of the Filchner-Ronne Ice Shelf Cavity Circulation and Basal Melt
	Hazel J.E.; Stewart A.L.
发表日期	2020
ISSN	21699275
卷号	125 期号:4
英文摘要	Circulation and water mass transformation within the Filchner-Ronne Ice Shelf (FRIS) cavity create precursors to Antarctic bottom water, which closes the global overturning circulation. This water mass transformation is contingent upon a relative low rate of FRIS basal melt, currently around 100–200 Gt/yr. Previous studies have indicated that Antarctic climate changes may induce intrusions of warm modified Warm Deep Water (mWDW) and an order-of-magnitude increase in basal melt, and signatures of mWDW have recently been observed along the face of the FRIS. However, it remains unclear how changes in near-Antarctic climate translate mechanistically to changes in mWDW access to the FRIS cavity. In this study a regional model is developed to investigate FRIS circulation dependence on local atmospheric state. Experiments with modified initial cavity conditions but identical atmospheric states yield bistable “warm” and “cold” FRIS cavity states, with an order-of-magnitude difference in basal melt rates. Idealized atmospheric perturbation experiments reveal that relatively modest perturbations to the katabatic winds shift the FRIS cavity between “warm” and “cold” states, which occur when the FRIS cavity is filled by mWDW or High Salinity Shelf Water (HSSW), respectively. The authors present a conceptual model in which the FRIS cavity state is determined by whether mWDW or HSSW is denser and thus floods the cavity; these states are bistable because the basal melt rate feeds back on the salinity of HSSW. These findings highlight a key role for the katabatic winds in mediating the melt of the FRIS and other Antarctic ice shelves. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	Filchner-Ronne Ice Shelf cavity; hysteresis; ice shelf melt; katabatic winds; regional modeling
语种	英语
来源期刊	Journal of Geophysical Research: Oceans
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/186919
作者单位	Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, United States
推荐引用方式 GB/T 7714	Hazel J.E.,Stewart A.L.. Bistability of the Filchner-Ronne Ice Shelf Cavity Circulation and Basal Melt[J],2020,125(4).
APA	Hazel J.E.,&Stewart A.L..(2020).Bistability of the Filchner-Ronne Ice Shelf Cavity Circulation and Basal Melt.Journal of Geophysical Research: Oceans,125(4).
MLA	Hazel J.E.,et al."Bistability of the Filchner-Ronne Ice Shelf Cavity Circulation and Basal Melt".Journal of Geophysical Research: Oceans 125.4(2020).