Hydrologic Impacts of Variations in the Albedo of Seasonal Snow

9417593否这项拟议研究的主要目的是研究和评估雪反照率的时空变异性如何影响季节性积雪融化的时间和强度，以及其他水文变量，包括土壤水分、潜在蒸散量和大气环流模式。中纬度和极地地区的季节性积雪和消融将使用大气环流模式(GCM)来模拟，该模式将利用时空变化的积雪反照率。目前GCM中雪反照率的参数化方法是基于温度、纬度和积雪深度，而不是雪的物理性质。将对GCM得出的积雪和雪水当量范围进行验证。将开发基于物理的雪反照率参数，以用于气候的数学模型。使用特定的GCM进行大规模积雪水文估算的可行性将被确定。还将评估在GCM中使用基于物理的、随时间和空间变化的雪反照率的可行性。将对遥感数据进行调查，以此作为评估GCM积雪估计准确性的一种手段。目前的气候模型对雪的反照率很敏感，但它们使用的是简单、不准确的参数化。需要对雪反照率与气候模型对雪反照率空间和时间变化的水文响应之间的关系进行全面研究。GMC对季节性降雪范围和深度的准确性仍未得到测试。

9417593 Nolin The primary objective of this proposed research is to examine and evaluate how the spatial and temporal variability of snow albedo affects the timing and intensity of seasonal snow melt and other hydrologic variables including soil moisture, potential evapotranspiration and atmospheric circulation patterns. Seasonal snow accumulation and ablation in both the mid-latitudes and the polar regions will be modeled using a general circulation model (GCM) with which spatially and temporally varying snow albedo will be employed. Current means of snow albedo parameterization in GCM's are based on temperature, latitude, and snow depth rather than the physical properties of snow. Validation of the GCM- derived extent of snowcover and snow water equivalent will be performed. Physically-based parameterizations of snow albedo will be developed for use in mathematical models of climate. The viability of using particular GCM's for large-scale snow hydrologic estimates will be determined. The feasibility of using physically- based, time- and space-variant snow albedos in a GCM will also be evaluated. Remote sensing data will be investigated as a means of assessing the accuracy of GCM snowcover estimates. Current models of climate are sensitive to snow albedo, yet they use simple, inaccurate parameterization. What is needed is a comprehensive study of the relationship between snow albedo and hydrologic response of climate models to sptial and temporal changes in snow albedo. GMC accuracy for seasonal snow extent and depth is still untested.