On the importance of sublimation to an alpine snow mass balance in the Canadian Rocky Mountains
On the importance of sublimation to an alpine snow mass balance in the Canadian Rocky Mountains
复制标题
DOI：
10.5194/hess-14-1401-2010
复制
发表时间：
2010-01-01
影响因子：
6.3
通讯作者：
Pietroniro, A.
中科院分区：
文献类型：
--
作者：
MacDonald, M. K.;Pomeroy, J. W.;Pietroniro, A.
进行了一项模拟研究，以评估升华的贡献，在加拿大落基山脉的高山雪质量平衡。在加拿大落基山脉的一个高山山脊样带上，模拟了两个冬季的雪再分布和风升华、积雪升华和融雪。由此产生的积雪制度进行了比较，从人工积雪调查。使用基于物理的吹雪（PBSM）和积雪消融（SNOBAL）模型进行模拟。水文响应单元（HRU）为基础的空间离散化，而不是一个更昂贵的计算全分布式。HRU的设置遵循空气动力学顺序，由此将侵蚀的雪从迎风的HRU输送到漂移累积的顺风HRU。雪再分配风可以充分模拟在计算效率HRU在这个山脊上有重要意义的代表雪运输在大尺度水文模型和陆面方案。高山雪升华损失，特别是吹雪升华损失，是显着的。据估计，升华损失的雪量占累积降雪量的20-32%，吹雪升华损失占累积降雪量的17-19%。这一估计被认为是加拿大落基山脉吹雪升华损失的保守估计，因为研究样带位于低高山区，地形比高山区更温和，没有观察到气流分离。PBSM的升华估计在这种环境中的适用性和估计吹雪升华对模拟积雪制度的重要性进行了检查省略升华计算。当忽略吹雪升华计算时，HRUs中的积雪被高估了30%。
A modelling study was undertaken to evaluate the contribution of sublimation to an alpine snow mass balance in the Canadian Rocky Mountains. Snow redistribution and sublimation by wind, snowpack sublimation and snowmelt were simulated for two winters over an alpine ridge transect located in the Canada Rocky Mountains. The resulting snowcover regimes were compared to those from manual snow surveys. Simulations were performed using physically based blowing snow (PBSM) and snowpack ablation (SNOBAL) models. A hydrological response unit (HRU)-based spatial discretization was used rather than a more computationally expensive fully-distributed one. The HRUs were set up to follow an aerodynamic sequence, whereby eroded snow was transported from windswept, upwind HRUs to drift accumulating, downwind HRUs. That snow redistribution by wind can be adequately simulated in computationally efficient HRUs over this ridge has important implications for representing snow transport in large-scale hydrology models and land surface schemes. Alpine snow sublimation losses, in particular blowing snow sublimation losses, were significant. Snow mass losses to sublimation as a percentage of cumulative snowfall were estimated to be 20-32% with the blowing snow sublimation loss amounting to 17-19% of cumulative snowfall. This estimate is considered to be a conservative estimate of the blowing snow sublimation loss in the Canadian Rocky Mountains because the study transect is located in the low alpine zone where the topography is more moderate than the high alpine zone and windflow separation was not observed. An examination of the suitability of PBSM's sublimation estimates in this environment and of the importance of estimating blowing snow sublimation on the simulated snow accumulation regime was conducted by omitting sublimation calculations. Snow accumulation in HRUs was overestimated by 30% when neglecting blowing snow sublimation calculations.