A distributed temperature-index ice- and snowmelt model including potential direct solar radiation
A distributed temperature-index ice- and snowmelt model including potential direct solar radiation
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DOI：
10.3189/s0022143000003087
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发表时间：
1999-01-01
影响因子：
3.4
通讯作者：
Hock, R
中科院分区：
文献类型：
--
作者：
Hock, R
对瑞典小冰川 Storglaciaren 的两个融化季节每小时的融化和排放量进行了计算，将温度指数方法应用于融化成分的 30 m 分辨率网格。经典的度日方法可以很好地模拟流量的季节性模式，但没有捕获明显的融化引起的每日流量周期。从分布式能量平衡模型获得的熔体中计算出的每小时和每个网格单元的建模度日因子在白天和空间上变化很大。建议采用一种新的分布式温度指数模型，试图捕获明显的昼夜融化周期和由于周围地形影响而导致的融化空间变化。这是通过包括潜在的晴空直接太阳辐射的辐射指数来实现的，因此除了气温之外不需要其他数据。这种方法大大改进了昼夜流量波动的模拟，并产生了更真实的熔化速率空间分布。纳入测量的全球辐射来解释由于多云导致的直接太阳辐射的减少并没有导致模型性能的进一步改善。
Hourly melt and discharge of Storglaciaren, a small glacier in Sweden, were computed for two melt seasons, applying temperature-index methods to a 30 m resolution grid for the melt component. The classical degree-day method yielded a good simulation of the seasonal pattern of discharge, but the pronounced melt-induced daily discharge cycles were not captured. Modelled degree-day factors calculated for every hour and each gridcell from melt obtained from a distributed energy-balance model varied substantially, bath diurnally and spatially. A new distributed temperature-index model is suggested, attempting to capture both the pronounced diurnal melt cycles and the spatial variations in melt due to the effects of surrounding topography. This is accomplished by including a radiation index in terms of potential clear-sky direct solar radiation, and thus, without the need for other data besides air temperature. This approach improved considerably the simulation of diurnal discharge fluctuations and yielded a more realistic spatial distribution of melt rates. The incorporation of measured global radiation to account for the reduction in direct solar radiation due to cloudiness did not lead to additional improvement in model performance.