Effects of local advection on the spatial sensible heat flux variation on a mountain glacier
Effects of local advection on the spatial sensible heat flux variation on a mountain glacier
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DOI：
10.5194/tc-10-2887-2016
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发表时间：
2016-11-24
期刊：
影响因子：
5.2
通讯作者：
Galos, Stephan Peter
中科院分区：
文献类型：
--
作者：
Sauter, Tobias;Galos, Stephan Peter
分布式质量平衡模型将微气象条件转化为当地的融化速率，已被证明不足以反映山区冰川的能量通量变化。这一缺陷主要与强迫数据中局部过程的代表性不足有关。我们发现，通过理想化的大涡模拟，热平流，与当地的风系统，导致小尺度感热通量的变化高达100 W m（-2）在晴朗的天空条件。在这里，我们表明，在几个观测点的过程的理解是不够的，以推断风和温度分布在整个冰川。当使用外推的温度和风场时，冰川范围内的小时平均感热通量被高估或低估了16 W m（-2）。差异的符号和幅度取决于用于外推的地点选择以及大尺度流动方向。我们的研究结果表明，在当地感热通量估计的缺点是如何与地形的影响和温度平流过程的不足表征。
Distributed mass balance models, which translate micrometeorological conditions into local melt rates, have proven deficient to reflect the energy flux variability on mountain glaciers. This deficiency is predominantly related to shortcomings in the representation of local processes in the forcing data. We found by means of idealized large-eddy simulations that heat advection, associated with local wind systems, causes small-scale sensible heat flux variations by up to 100 W m(-2) during clear sky conditions. Here we show that process understanding at a few observation sites is insufficient to infer the wind and temperature distributions across the glacier. The glacier-wide hourly averaged sensible heat fluxes are both over-and underestimated by up to 16 W m(-2) when using extrapolated temperature and wind fields. The sign and magnitude of the differences depend on the site selection, which is used for extrapolation as well as on the large-scale flow direction. Our results demonstrate how the shortcomings in the local sensible heat flux estimates are related to topographic effects and the insufficient characterization of the temperature advection process.