Seasonal snow cover affects markedly the albedo values of the boreal forest zone. It increases the forest albedo values and changes the diurnal variation of albedo compared to snow-free situations. Snow is also a high scatterer in visible and near-infrared wavelengths, and thus the probability of multiple scattering between forest floor and canopy is high. A photon recollision probability based model called PARAS, where multiple scattering components are included, was used to simulate albedo values of needleleaved evergreen forest with and without snow cover on the forest floor. We focused on two example dates representing typical premelt and melting season snow conditions in clear-sky cases, and multiple overcast days over melting season, and compared the diurnal and seasonal variations to estimate the effect of snow cover and multiple scattering. We found that changing the forest floor surface from snow-free to snow-covered changes the diurnal variation characteristics of the clear-sky albedo from U-shaped to W-shaped. In addition, ignoring the effect of the forest floor or multiple scattering leads to relative underestimation of forest albedo values and reflected solar energy, of up to 80% (up to 1.0 kWh/m²) and 30% (up to 0.25 kWh/m²), respectively. The underestimations depend on the forest floor cover type and the season.

季节性积雪明显影响了北方森林带的反照率。与无雪情况相比，它增加了森林的反照率值并改变了反照率的日变化。雪也是可见光和近红外波长的高散射体，因此林地和冠层之间多次散射的可能性很高。基于光子碰撞概率的模型称为PARAS，其中包括多个散射成分，用于模拟针叶常绿森林在有林和无雪的情况下的反照率值。我们重点研究了两个示例日期，这些日期代表晴空情况下典型的预融雪和融雪季节的雪况，以及融雪季节的多个阴天，并比较了昼夜和季节变化以估计积雪和多次散射的影响。我们发现，将森林地表表面从无雪改变为积雪可以将晴空反射率的日变化特征从U形改变为W形。此外，忽略森林地面或多重散射的影响会导致相对低估森林反照率值和反射太阳能，最高可达80％（最高1.0 kWh / m²）和30％（最高0.25 kWh / m ²）。低估取决于森林地面覆盖物类型和季节。