Modelling glacier mass changes on regional and global scales

全球范围内的山地冰川和冰盖的退缩是最近气候变化的关键指标之一。在全球范围内，冰川的质量损失导致海平面上升。在区域和地方尺度上，冰川融水是一年中干旱和温暖时期河流流量的重要贡献者。在加拿大西部，冰川径流维持低流量对维持水生生态系统和水力发电至关重要。此外，加拿大西部和加拿大北极地区的冰川对海平面上升起了很大的作用，预计在今后50-100年内仍将如此。目前，在区域和全球范围内预测冰川质量变化的尝试依赖于简化的数值模型，其中冰川融化的数量仅取决于气温。由于其简单性，这些基于几何的模型被广泛用于模拟冰川和冰盖的质量变化，然而，它们忽略了重要的表面能量项，如太阳辐射和潜热。一个物理上更正确的方法是应用能量质量平衡模型，跟踪影响冰川表面的所有能量项。本研究的总体目标是通过开发区域尺度的能量质量平衡模型来改进我们在模拟冰川对气候变化的响应方面的尝试。最初，研究区域将包括加拿大西部的所有冰川。冰川模式将由中尺度大气模式的高分辨率气候场所推动。将建立一个由该区域几个不同冰川地点组成的监测网络，以生成可用于验证质量平衡模型的高质量能量和质量通量数据。拟议的研究将通过调查冰川表面的全部能量耦合来提高我们对冰川-大气界面过程的理解，并改进区域尺度上冰川质量变化的建模，缩小冰川质量损失预测的不确定性。

Retreat of mountain glaciers and ice caps worldwide is one of the key indicators of recent climate change. On a global scale, the mass loss from glaciers contributes to sea level rise. On a regional and local scale, glacier melt-water is an important contributor to river flow during dry and warm parts of the year. In western Canada, maintenance of low flows by glacier runoff is essential to sustain aquatic ecosystems and hydropower generation. Furthermore, glaciers of western Canada and the Canadian Arctic substantially contribute to sea level rise and are expected to do so for the next 50-100 years. Current attempts to project glacier mass changes on regional and global scale rely on simplified numerical models where the amount of glacier melt depends only on air temperature. Because of their simplicity, these empirically-based models are widely used to simulate mass change of glaciers and ice sheets, however, they neglect important surface energy terms such as solar radiation and latent heat. A more physically correct approach is to apply an energy mass balance model that tracks all energy terms that affect the surface of a glacier. The overall aim of this study is to improve our attempts at modelling glacier response to climate change by developing an energy mass-balance model on regional scale. Initially, the study area will consist of all the glaciers in western Canada. The glacier model will be forced by high-resolution climate fields from a mesoscale atmospheric model. A monitoring network of several different glacier sites in the domain will be installed in order to generate high-quality energy and mass flux data that can be used to validate the mass-balance model. The proposed research will improve our understanding of processes at the glacier-atmosphere interface by investigating full energy coupling at the glacier surface, and improve modelling of glacier mass changes on regional scales, narrowing the uncertainties in the projections of glacier mass loss.