气候变化领域集成服务门户(CCPortal): Causal interactions between southern ocean polynyas and high-latitude atmosphere-ocean variability

CCPortal

DOI	10.1175/JCLI-D-19-0525.1
	Causal interactions between southern ocean polynyas and high-latitude atmosphere-ocean variability
	Kaufman Z.S.; Feldl N.; Weijer W.; Veneziani M.
发表日期	2020
ISSN	0894-8755
起始页码	4891
结束页码	4905
卷号	33 期号:11
英文摘要	Weddell Sea open-ocean polynyas have been observed to occasionally release heat from the deep ocean to the atmosphere, indicating that their sporadic appearances may be an important feature of high-latitude atmosphere-ocean variability. Yet, observations of the phenomenon are sparse and many standardresolution models represent these features poorly, if at all. We use a fully coupled, synoptic-scale preindustrial control simulation of the Energy Exascale Earth System Model (E3SMv0-HR) to effectively simulate open-ocean polynyas and investigate their role in the climate system. Our approach employs statistical tests of Granger causality to diagnose local and remote drivers of, and responses to, polynya heat loss on interannual to decadal time scales. First, we find that polynya heat loss Granger causes a persistent increase in surface air temperature over the Weddell Sea, strengthening the local cyclonic wind circulation. Along with responding to polynyas, atmospheric conditions also facilitate their development.When the Southern Ocean experiences a rapid poleward shift in the circumpolar westerlies following a prolonged negative phase of the southern annular mode (SAM), Weddell Sea salinity increases, promoting density destratification and convection in the water column. Finally, we find that the reduction of surface heat fluxes during periods of full ice cover is not fully compensated by ocean heat transport into the high latitudes. This imbalance leads to a buildup of ocean heat content that supplies polynya heat loss. These results disentangle the complex, coupled climate processes that both enable the polynya's existence and respond to it, providing insights to improve the representation of these highly episodic sea ice features in climate models. © 2020 American Meteorological Society.
英文关键词	Atmospheric thermodynamics; Climate models; Heat flux; Heat losses; Sea ice; Statistical tests; Atmosphere ocean variability; Atmospheric conditions; Control simulation; Ocean heat content; Ocean heat transport; Southern Annular Mode; Surface air temperatures; Surface heat fluxes; Oceanography; air-sea interaction; annual variation; atmosphere-ocean coupling; climate modeling; decadal variation; latitudinal gradient; polynya; sea ice; Southern Ocean; Weddell Sea
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/171277
作者单位	University of California, Santa Cruz, Santa Cruz, CA, United States; Los Alamos National Laboratory, Los Alamos, NM, United States
推荐引用方式 GB/T 7714	Kaufman Z.S.,Feldl N.,Weijer W.,et al. Causal interactions between southern ocean polynyas and high-latitude atmosphere-ocean variability[J],2020,33(11).
APA	Kaufman Z.S.,Feldl N.,Weijer W.,&Veneziani M..(2020).Causal interactions between southern ocean polynyas and high-latitude atmosphere-ocean variability.Journal of Climate,33(11).
MLA	Kaufman Z.S.,et al."Causal interactions between southern ocean polynyas and high-latitude atmosphere-ocean variability".Journal of Climate 33.11(2020).