气候变化领域集成服务门户(CCPortal): Seasonal and interannual variability of melt-season albedo at Haig Glacier, Canadian Rocky Mountains

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DOI	10.5194/tc-14-3249-2020
	Seasonal and interannual variability of melt-season albedo at Haig Glacier, Canadian Rocky Mountains
	Marshall S.J.; Miller K.
发表日期	2020
ISSN	19940416
起始页码	3249
结束页码	3267
卷号	14 期号:10
英文摘要	In situ observations of summer (June through August, or JJA) albedo are presented for the period 2002–2017 from Haig Glacier in the Canadian Rocky Mountains. The observations provide insight into the seasonal evolution and interannual variability of snow and ice albedo, including the effects of summer snowfall, the decay of snow albedo through the melt season, and the potential short-term impacts of regional wildfire activity on glacier-albedo reductions. Mean JJA albedo (1) recorded at an automatic weather station in the upper ablation zone of the glacier was S D 0:55-0.07 over this period, with no evidence of longterm trends in surface albedo. Each summer the surface conditions at the weather station undergo a transition from a dry, reflective spring snowpack (S 0:8) to a wet, homogeneous midsummer snowpack (S 0:5) to exposed, impurity-rich glacier ice, with a measured albedo of 0.21 0.06 over the study period. The ice albedo drops to -0.12 during years of intense regional wildfire activity such as 2003 and 2017, but it recovers from this in subsequent years. This seasonal albedo decline is well simulated through a parameterization of snow-albedo decay based on cumulative positive degree days (PDDs), but the parameterization does not capture the impact of summer snowfall events, which cause transient increases in albedo and significantly reduce glacier melt. We introduce this effect through a stochastic parameterization of summer precipitation events within a surface energy balance model. The amount of precipitation and the date of snowfall are randomly selected for each model realization based on a predefined number of summer snow events. This stochastic parameterization provides an improved representation of the mean summer albedo and mass balance at Haig Glacier. We also suggest modifications to conventional degree-day melt factors to better capture the effects of seasonal albedo evolution in temperature-index or positive-degree-day melt models on mountain glaciers. Climate, hydrology, or glacier mass balance models that use these methods typically use a binary rather than continuum approach to prescribing melt factors, with one melt factor for snow and one for ice. As alternatives, monthly melt factors effectively capture the seasonal albedo evolution, or melt factors can be estimated as a function of the albedo where these data are available. >© 2020 Copernicus GmbH. All rights reserved.
英文关键词	ablation; albedo; energy balance; glacier mass balance; mass balance; melting; mountain environment; parameterization; seasonal variation; snowpack; surface energy; weather station; wildfire; Canada; Haig Glacier; Rocky Mountains
语种	英语
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/202155
作者单位	Department of Geography, University of Calgary, Calgary, AB T2N 1N4, Canada; Environment and Climate Change Canada, Gatineau, QC, Canada
推荐引用方式 GB/T 7714	Marshall S.J.,Miller K.. Seasonal and interannual variability of melt-season albedo at Haig Glacier, Canadian Rocky Mountains[J],2020,14(10).
APA	Marshall S.J.,&Miller K..(2020).Seasonal and interannual variability of melt-season albedo at Haig Glacier, Canadian Rocky Mountains.Cryosphere,14(10).
MLA	Marshall S.J.,et al."Seasonal and interannual variability of melt-season albedo at Haig Glacier, Canadian Rocky Mountains".Cryosphere 14.10(2020).