Measurement and parameterization of aerodynamic roughness length variations at Haut Glacier d'Arolla, Switzerland
Measurement and parameterization of aerodynamic roughness length variations at Haut Glacier d'Arolla, Switzerland
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DOI：
10.3189/172756506781828746
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发表时间：
2006-03
影响因子：
3.4
通讯作者：
B. Brock;I. Willis;M. Sharp
中科院分区：
文献类型：
--
作者：
B. Brock;I. Willis;M. Sharp
根据表面微地形的测量，描述了 1993 年和 1994 年消融季节瑞士阿罗拉上冰川空气动力粗糙度长度 (z0) 的空间和时间变化。微地形 z0 测量的有效性是通过与融化的雪、雪泥和冰上的独立垂直风廓线 z0 测量进行比较来确定的。 z0 变化通过相关和回归分析、使用气象和地表变量的独立测量来解释，并且开发参数化来计算 z0 变化以用于表面能量平衡熔体模型。几个自变量通过它们与积雪融化过程中由烧蚀空洞形成引起的表面粗糙度增加的相关性，成功地解释了积雪 z0 的变化。基于自最近降雪以来累积融化或累积每日最高温度的非线性参数化解释了超过 80% 的雪 z0 变化。冰面上新降雪后的 z0 根据与底层冰 z0、雪深和累积每日最高温度的关系进行参数化。没有一个自变量能够成功解释ice z0 的变化。尽管还需要进一步的比较研究，但结果为测量融化冰川表面 z0 的微地形技术提供了强有力的支持。
Spatial and temporal variations in aerodynamic roughness length (z0) on Haut Glacier d'Arolla, Switzerland, during the 1993 and 1994 ablation seasons are described, based on measure- ments of surface microtopography. The validity of the microtopographic z0 measurements is established through comparison with independent vertical wind profile z0 measurements over melting snow, slush and ice. The z0 variations are explained through correlation and regression analyses, using independent measurements of meteorological and surface variables, and parameterizations are developed to calculate z0 variations for use in surface energy balance melt models. Several independent variables successfully explain snow z0 variation through their correlation with increasing surface roughness, caused by ablation hollow formation, during snow melt. Non-linear parameterizations based on either accumulated melt or accumulated daily maximum temperatures since the most recent snowfall explain over 80% of snow z0 variation. The z0 following a fresh snowfall on an ice surface is parameterized based on relationships with the underlying ice z0, snow depth and accumulated daily maximum temperatures. None of the independent variables were able to successfully explain ice z0 variation. Although further comparative studies are needed, the results lend strong support to the microtopo- graphic technique of measuring z0 over melting glacier surfaces.