DOI: 10.5194/tc-9-255-2015
Scopus记录号: 2-s2.0-84922514539
论文题名: Regional melt-pond fraction and albedo of thin Arctic first-year drift ice in late summer
作者: Divine D ; V ; , Granskog M ; A ; , Hudson S ; R ; , Pedersen C ; A ; , Karlsen T ; I ; , Divina S ; A ; , Renner A ; H ; H ; , Gerland S
刊名: Cryosphere
ISSN: 19940416
出版年: 2015
卷: 9, 期: 1 起始页码: 255
结束页码: 268
语种: 英语
英文关键词: albedo
; ice drift
; image classification
; marginal ice zone
; meltwater
; optical property
; sea ice
; solar radiation
; statistical analysis
; summer
; uncertainty analysis
; upscaling
; Arctic Ocean
英文摘要: The paper presents a case study of the regional (g‰150 km) morphological and optical properties of a relatively thin, 70-90 cm modal thickness, first-year Arctic sea ice pack in an advanced stage of melt. The study combines in situ broadband albedo measurements representative of the four main surface types (bare ice, dark melt ponds, bright melt ponds and open water) and images acquired by a helicopter-borne camera system during ice-survey flights. The data were collected during the 8-day ICE12 drift experiment carried out by the Norwegian Polar Institute in the Arctic, north of Svalbard at 82.3° N, from 26 July to 3 August 2012. A set of > 10 000 classified images covering about 28 km2 revealed a homogeneous melt across the study area with melt-pond coverage of g‰ 0.29 and open-water fraction of g‰ 0.11. A decrease in pond fractions observed in the 30 km marginal ice zone (MIZ) occurred in parallel with an increase in open-water coverage. The moving block bootstrap technique applied to sequences of classified sea-ice images and albedo of the four surface types yielded a regional albedo estimate of 0.37 (0.35; 0.40) and regional sea-ice albedo of 0.44 (0.42; 0.46). Random sampling from the set of classified images allowed assessment of the aggregate scale of at least 0.7 km2 for the study area. For the current setup configuration it implies a minimum set of 300 images to process in order to gain adequate statistics on the state of the ice cover. Variance analysis also emphasized the importance of longer series of in situ albedo measurements conducted for each surface type when performing regional upscaling. The uncertainty in the mean estimates of surface type albedo from in situ measurements contributed up to 95% of the variance of the estimated regional albedo, with the remaining variance resulting from the spatial inhomogeneity of sea-ice cover. © Author(s) 2015. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75364
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: Norwegian Polar Institute, Fram Centre, Tromsø, Norway; Department of Mathematics and Statistics, Faculty of Science and Technology, University of Tromsø, Tromsø, Norway; Institute of Marine Research, Sykehusveien 23, Tromsø, Norway
Recommended Citation:
Divine D,V,, Granskog M,et al. Regional melt-pond fraction and albedo of thin Arctic first-year drift ice in late summer[J]. Cryosphere,2015-01-01,9(1)