DOI: 10.5194/tc-10-665-2016
Scopus记录号: 2-s2.0-84962520834
论文题名: Estimating ice albedo from fine debris cover quantified by a semi-automatic method: The case study of Forni Glacier, Italian Alps
作者: Sergio Azzoni R ; , Senese A ; , Zerboni A ; , Maugeri M ; , Smiraglia C ; , Adele Diolaiuti G
刊名: Cryosphere
ISSN: 19940416
出版年: 2016
卷: 10, 期: 2 起始页码: 665
结束页码: 679
语种: 英语
英文关键词: ablation
; albedo
; algorithm
; fines
; ice-rafted debris
; image analysis
; image resolution
; in situ measurement
; meltwater
; precipitation intensity
; valley glacier
; Alps
; Forni Glacier
; Italy
; Lombardy
; Sondrio
英文摘要: In spite of the quite abundant literature focusing on fine debris deposition over glacier accumulation areas, less attention has been paid to the glacier melting surface. Accordingly, we proposed a novel method based on semi-automatic image analysis to estimate ice albedo from fine debris coverage (d). Our procedure was tested on the surface of a wide Alpine valley glacier (the Forni Glacier, Italy), in summer 2011, 2012 and 2013, acquiring parallel data sets of in situ measurements of ice albedo and high-resolution surface images. Analysis of 51 images yielded d values ranging from 0.01 to 0.63 and albedo was found to vary from 0.06 to 0.32. The estimated d values are in a linear relation with the natural logarithm of measured ice albedo (R =-0.84). The robustness of our approach in evaluating d was analyzed through five sensitivity tests, and we found that it is largely replicable. On the Forni Glacier, we also quantified a mean debris coverage rate (Cr) equal to 6gm-2 per day during the ablation season of 2013, thus supporting previous studies that describe ongoing darkening phenomena at Alpine debris-free glaciers surface. In addition to debris coverage, we also considered the impact of water (both from melt and rainfall) as a factor that tunes albedo: meltwater occurs during the central hours of the day, decreasing the albedo due to its lower reflectivity; instead, rainfall causes a subsequent mean daily albedo increase slightly higher than 20 %, although it is short-lasting (from 1 to 4 days). © 2016 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75168
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: Università Degli Studi di Milano, Dipartimento di Scienze della Terra A. Desio, Milan, Italy; Università Degli Studi di Milano, Dipartimento di Fisica, Milan, Italy
Recommended Citation:
Sergio Azzoni R,, Senese A,, Zerboni A,et al. Estimating ice albedo from fine debris cover quantified by a semi-automatic method: The case study of Forni Glacier, Italian Alps[J]. Cryosphere,2016-01-01,10(2)