DOI: 10.5194/tc-8-891-2014
Scopus记录号: 2-s2.0-84900843605
论文题名: The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: A model study
作者: Willmes S ; , Nicolaus M ; , Haas C
刊名: Cryosphere
ISSN: 19940416
出版年: 2014
卷: 8, 期: 3 起始页码: 891
结束页码: 904
语种: 英语
英文关键词: brightness temperature
; climate forcing
; emissivity
; melting
; satellite imagery
; sea ice
; seasonal variation
; snow cover
; Antarctica
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). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/74845
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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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
Recommended Citation:
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]. Cryosphere,2014-01-01,8(3)