Historic Glacier Change in the Western US: Database and Modeling

这项提议开发了一个全面的地理信息系统数据库，记录了美国西部(不包括阿拉斯加)历史上的冰川变化。我们将根据地形图和存储在联邦和州机构档案馆、大学图书馆和徒步旅行俱乐部中的航空和地面图像的历史记录，定义美国西部冰川的空间范围和时间变化。我们希望在不同的时间为西部的每一座冰川找到至少两个范围。在一些游客较多的地区(如Mt.冰川国家公园)随着时间的推移，我们会发现许多冰川的范围。这些数据将在地理信息系统数据库中汇编，并从中得出变化量和变化率。该数据库将通过万维网向公众开放，供专业人士、教育工作者和公众使用。除了冰川范围的形状文件，我们还将包括照片和参考书目，如果有的话。仅这一成就就将加速我们对冰川变化的空间和时间模式的理解。在没有地形数据的情况下，将通过面积-体积比例方程来估计体积变化。这是确定冰川消融对河流流量和全球海平面上升影响的关键一步。我们还将测试元胞自动机方法是否可以合理地预测给定高山地区内个别高山冰川的位置和几何形状。该模型将由气候驱动，并使用一套基于冰川物理简化的规则，在已知地形表面上以数字方式将冰川生长到平衡几何形状。

This proposal develops a comprehensive GIS database of historic glacierchange in the American west, exclusive of Alaska. We will define thespatial extent and temporal variation of glaciers in the American westbased on the historic record derived from topographic maps and from aerialand ground-based images stored in federal and state agency archives,university libraries, and in hiking clubs. We expect to find at least twoextents at different times for every glacier in the west. In some wellvisited areas (e.g. Mt. Rainier, Glacier National Park) we will find manyglacier extents over time. These data will be compiled in a GIS databasefrom which the magnitude and rates of change will be derived. Thedatabase will be made publicly available via the world wide web for use byprofessionals, educators, and the general public. In addition to theshape files of glacier extent, we will include photographs andbibliographic references when available. This achievement alone willaccelerate our understanding of spatial and temporal patterns of glacierchange. Volume changes will be estimated, where topographic data areabsent, through area-volume scaling equations. This is a critical steptowards defining the effect of glacier mass wastage on stream flow andglobal sea level rise. We will also test whether a cellular automataapproach can reasonably predict the location and geometry of individualalpine glaciers within a given alpine region. The model will be driven byclimate and numerically grow glaciers to an equilibrium geometry on theknown topographic surface using a set of rules based on a simplificationof glacier physics.