Solar Radiation Transfer Through a Subarctic Shrub Canopy
Solar Radiation Transfer Through a Subarctic Shrub Canopy
复制标题
太阳辐射通过亚北极灌木冠层的传输
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
R. Essery
中科院分区：
文献类型：
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作者：
D. Bewley;J. Pomeroy;R. Essery
ABSTRACT Much of the low Arctic is covered with shrubs that are partially buried by snow in winter and become exposed during melt. This study presents measurements and modeling of shortwave radiation reflection and extinction by a deciduous shrub canopy emerging from a melting snowcover in the mountains of the Yukon Territory, Canada. Shrubs shade most of the snow surface at low solar elevation angles, so only a fraction of the incoming radiation reaches the surface, but there is greater direct shortwave transmission to the surface in gaps between shrubs for higher solar elevations. A simple model is developed to incorporate the changing contributions of sun-lit gaps, shaded gaps, and shrubs to the landscape-averaged (areal) transmission and reflection of shortwave radiation. The areal transmissivity and albedo in this model are lower than in a two-stream approximation that neglects gap shading. A simple shadow parameterization is proposed for calculating shrub tundra snowmelt rates and surface energy balances in hydrological and land-surface models.
