Approaches to Modelling the Surface Albedo of a High Arctic Glacier
Approaches to Modelling the Surface Albedo of a High Arctic Glacier
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北极高冰川表面反照率建模方法
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发表时间：
1999
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通讯作者：
A. Arendt
中科院分区：
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作者：
A. Arendt
在夏季融化季节，John Evans冰川（79°40′n, 74°00′w）上的三个气象站进行了宽带地表反照率测量，结果显示地表反照率随太阳天顶角（θ 2）的变化很大。从反照率测量中去除日信号，通过每日平均每小时测量，或通过将正午测量应用于一天中的所有小时，K *的变化高达16%。忽略在θ z bbb75°处进行的测量，以解释在高θ z处的测量（余弦）误差，K *降低了5%到18%。考虑到K *对地表反照率日变化的敏感性，用两种反照率模型进行了实验。一个模型解释了反照率随θ z的变化，另一个没有。由θ z驱动的模型在约翰·埃文斯冰川的表面能量平衡模型中得到了更好的融化估计。这表明地表反照率的日变化应该在冰川融化的能量平衡模型中考虑。
Broadband surface albedo measurements, made during the summer melt season at three weather stations on John Evans Glacier (79°40'N, 74°00'W), varied strongly with the solar zenith angle (θ 2 ) Tests were carried out to assess the impact of diurnal variations in surface albedo on seasonal net shortwave radiation (K * ) totals. Removing the diurnal signal from albedo measurements by daily averaging of hourly measurements, or by applying midday measurements to all hours of the day, changed K * by up to 16%. Ignoring measurements made at θ z > 75°, to account for measurement (cosine) error at high θ z , decreased K * by between 5 and 18%. Given the sensitivity of K * to diurnal patterns in surface albedo, experiments were carried out with two albedo models. One model accounted for albedo variations with θ z and one did not. The model driven by θ z , when implemented within a surface energy balance model for John Evans Glacier, produced better melt estimates. This suggests that diurnal variations in surface albedo should be accounted for in energy balance models of glacier melt.