气候变化领域集成服务门户(CCPortal): Sea-ice indicators of polar bear habitat

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DOI	10.5194/tc-10-2027-2016
	Sea-ice indicators of polar bear habitat
	Stern H.L.; Laidre K.L.
发表日期	2016
ISSN	19940416
卷号	10 期号:5
英文摘要	Nineteen subpopulations of polar bears (Ursus maritimus) are found throughout the circumpolar Arctic, and in all regions they depend on sea ice as a platform for traveling, hunting, and breeding. Therefore polar bear phenology - the cycle of biological events - is linked to the timing of sea-ice retreat in spring and advance in fall. We analyzed the dates of sea-ice retreat and advance in all 19 polar bear subpopulation regions from 1979 to 2014, using daily sea-ice concentration data from satellite passive microwave instruments. We define the dates of sea-ice retreat and advance in a region as the dates when the area of sea ice drops below a certain threshold (retreat) on its way to the summer minimum or rises above the threshold (advance) on its way to the winter maximum. The threshold is chosen to be halfway between the historical (1979-2014) mean September and mean March sea-ice areas. In all 19 regions there is a trend toward earlier sea-ice retreat and later sea-ice advance. Trends generally range from -3 to -9daysdecade-1 in spring and from +3 to +9daysdecade-1 in fall, with larger trends in the Barents Sea and central Arctic Basin. The trends are not sensitive to the threshold. We also calculated the number of days per year that the sea-ice area exceeded the threshold (termed ice-covered days) and the average sea-ice concentration from 1 June through 31 October. The number of ice-covered days is declining in all regions at the rate of -7 to -19daysdecade-1, with larger trends in the Barents Sea and central Arctic Basin. The June-October sea-ice concentration is declining in all regions at rates ranging from -1 to -9percentdecade-1. These sea-ice metrics (or indicators of habitat change) were designed to be useful for management agencies and for comparative purposes among subpopulations. We recommend that the National Climate Assessment include the timing of sea-ice retreat and advance in future reports. © Author(s) 2016.
学科领域	arctic environment; bear; concentration (composition); environmental indicator; habitat availability; ice retreat; microwave radiometer; phenology; satellite data; sea ice; subpopulation; trend analysis; Arctic Ocean; Ursus maritimus
语种	英语
scopus关键词	arctic environment; bear; concentration (composition); environmental indicator; habitat availability; ice retreat; microwave radiometer; phenology; satellite data; sea ice; subpopulation; trend analysis; Arctic Ocean; Ursus maritimus
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119585
作者单位	Polar Science Center, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA 98105, United States; Greenland Institute of Natural Resources, Nuuk, 3900, Greenland
推荐引用方式 GB/T 7714	Stern H.L.,Laidre K.L.. Sea-ice indicators of polar bear habitat[J],2016,10(5).
APA	Stern H.L.,&Laidre K.L..(2016).Sea-ice indicators of polar bear habitat.Cryosphere,10(5).
MLA	Stern H.L.,et al."Sea-ice indicators of polar bear habitat".Cryosphere 10.5(2016).