气候变化领域集成服务门户(CCPortal): The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: A model study

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DOI	10.5194/tc-8-891-2014
	The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: A model study
	Willmes S.; Nicolaus M.; Haas C.
发表日期	2014
ISSN	19940416
卷号	8 期号:3
英文摘要	Satellite observations of microwave brightness temperatures between 19 GHz and 85 GHz are the main data sources for operational sea-ice monitoring and retrieval of ice concentrations. However, microwave brightness temperatures depend on the emissivity of snow and ice, which is subject to pronounced seasonal variations and shows significant hemispheric contrasts. These mainly arise from differences in the rate and strength of snow metamorphism and melt. We here use the thermodynamic snow model SNTHERM forced by European Re-Analysis (ERA) interim data and the Microwave Emission Model of Layered Snowpacks (MEMLS), to calculate the sea-ice surface emissivity and to identify the contribution of regional patterns in atmospheric conditions to its variability in the Arctic and Antarctic. The computed emissivities reveal a pronounced seasonal cycle with large regional variability. The emissivity variability increases from winter to early summer and is more pronounced in the Antarctic. In the pre-melt period (January-May, July-November) the standard deviations in surface microwave emissivity due to diurnal, regional and inter-annual variability of atmospheric forcing reach up to Î"Îμ Combining double low line 0.034, 0.043, and 0.097 for 19 GHz, 37 GHz and 85 GHz channels, respectively. Between 2000 and 2009, small but significant positive emissivity trends were observed in the Weddell Sea during November and December as well as in Fram Strait during February, potentially related to earlier melt onset in these regions. The obtained results contribute to a better understanding of the uncertainty and variability of sea-ice concentration and snow-depth retrievals in regions of high sea-ice concentrations. © 2014 Author(s).
学科领域	brightness temperature; climate forcing; emissivity; melting; satellite imagery; sea ice; seasonal variation; snow cover; Antarctica
语种	英语
scopus关键词	brightness temperature; climate forcing; emissivity; melting; satellite imagery; sea ice; seasonal variation; snow cover; Antarctica
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/120112
作者单位	University of Trier Environmental Meteorology, 54286 Trier, Germany; Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung, Bremerhaven, Germany; Dept. of Earth and Space Science and Engineering, York University, Toronto, Canada
推荐引用方式 GB/T 7714	Willmes S.,Nicolaus M.,Haas C.. The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: A model study[J],2014,8(3).
APA	Willmes S.,Nicolaus M.,&Haas C..(2014).The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: A model study.Cryosphere,8(3).
MLA	Willmes S.,et al."The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: A model study".Cryosphere 8.3(2014).