气候变化领域集成服务门户(CCPortal): Representing moisture fluxes and phase changes in glacier debris cover using a reservoir approach

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DOI	10.5194/tc-8-1429-2014
	Representing moisture fluxes and phase changes in glacier debris cover using a reservoir approach
	Collier E.; Nicholson L.I.; Brock B.W.; Maussion F.; Essery R.; Bush A.B.G.
发表日期	2014
ISSN	19940416
卷号	8 期号:4
英文摘要	Due to the complexity of treating moisture in supraglacial debris, surface energy balance models to date have neglected moisture infiltration and phase changes in the debris layer. The latent heat flux (QL) is also often excluded due to the uncertainty in determining the surface vapour pressure. To quantify the importance of moisture on the surface energy and climatic mass balance (CMB) of debris-covered glaciers, we developed a simple reservoir parameterization for the debris ice and water content, as well as an estimation of the latent heat flux. The parameterization was incorporated into a CMB model adapted for debris-covered glaciers. We present the results of two point simulations, using both our new "moist" and the conventional "dry" approaches, on the Miage Glacier, Italy, during summer 2008 and fall 2011. The former year coincides with available in situ glaciological and meteorological measurements, including the first eddy-covariance measurements of the turbulent fluxes over supraglacial debris, while the latter contains two refreeze events that permit evaluation of the influence of phase changes. The simulations demonstrate a clear influence of moisture on the glacier energy and mass-balance dynamics. When water and ice are considered, heat transmission to the underlying glacier ice is lower, as the effective thermal diffusivity of the saturated debris layers is reduced by increases in both the density and the specific heat capacity of the layers. In combination with surface heat extraction by QL, subdebris ice melt is reduced by 3.1% in 2008 and by 7.0% in 2011 when moisture effects are included. However, the influence of the parameterization on the total accumulated mass balance varies seasonally. In summer 2008, mass loss due to surface vapour fluxes more than compensates for the reduction in ice melt, such that the total ablation increases by 4.0%. Conversely, in fall 2011, the modulation of basal debris temperature by debris ice results in a decrease in total ablation of 2.1%. Although the parameterization is a simplified representation of the moist physics of glacier debris, it is a novel attempt at including moisture in a numerical model of debris-covered glaciers and one that opens up additional avenues for future research. © Author(s) 2014.
学科领域	ablation; debris flow; eddy covariance; glacier mass balance; heat flux; infiltration; measurement method; numerical model; parameterization; reservoir; water content; Italy; Miage Glacier; Valle d'Aosta
语种	英语
scopus关键词	ablation; debris flow; eddy covariance; glacier mass balance; heat flux; infiltration; measurement method; numerical model; parameterization; reservoir; water content; Italy; Miage Glacier; Valle d'Aosta
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/120075
作者单位	Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Canada; Institute of Meteorology and Geophysics, University of Innsbruck, Innsbruck, Austria; Geography Department, Northumbria University, Newcastle-upon-Tyne, United Kingdom; Department of Climatology, Technische Universität Berlin, Berlin, Germany; School of Geosciences, University of Edinburgh, Edinburgh, United Kingdom
推荐引用方式 GB/T 7714	Collier E.,Nicholson L.I.,Brock B.W.,et al. Representing moisture fluxes and phase changes in glacier debris cover using a reservoir approach[J],2014,8(4).
APA	Collier E.,Nicholson L.I.,Brock B.W.,Maussion F.,Essery R.,&Bush A.B.G..(2014).Representing moisture fluxes and phase changes in glacier debris cover using a reservoir approach.Cryosphere,8(4).
MLA	Collier E.,et al."Representing moisture fluxes and phase changes in glacier debris cover using a reservoir approach".Cryosphere 8.4(2014).