Collaborative Research: Feedbacks between Orographic Precipitation and Ice Dynamics

Aschwanden/1644277该奖项支持一个研究南极半岛雨影现象（技术上称为地形降水）及其与冰雪覆盖的山脉相互作用的项目。地形降水造成地球上最大的气候和生态梯度。 在山脉迎风面上升的空气膨胀和冷却，冷凝它携带的水蒸气，产生大雨或降雪。当空气在背风侧下降时，空气变暖变干，几乎没有降水。 这种降雪模式是由风和景观的相互作用引起的，据推测是为了控制冰盖本身的形状。研究人员假设，降水和地形之间的反馈控制冰通量和温度，影响基础条件（冻结与潮湿）和运动，在长时间尺度上可以通过侵蚀影响基底地形。作者建议研究地形驱动的降水，冰动力学，热力学，通过将一个地形降水模式与平行冰盖模式（PISM）耦合，模拟了北方南极半岛的底部侵蚀和隆起。使用理想化和更现实的几何形状，他们将开始一个二维流动带模型，将扩展到三维，以确定作为基岩几何形状和地形降水梯度强度的函数的反馈强度。南极半岛是一个理想的案例研究，在其快速的现代和未来的变化，以及自末次冰期以来的通缩的背景下。 这项工作的更广泛影响包括通过捕获与当前模型中未包括的地形降水有关的反馈来加强预测模型。这可能会提供一个更现实的评估在不断变化的气候制度的地形降水的影响。该项目将支持一名早期职业科学家和一名女性职业中期科学家，并将支持一名博士生，并为一名本科生提供夏季研究经验作为REU补充。 该项目不需要在南极进行实地考察。

Aschwanden/1644277This award supports a project to study the phenomenon of the rain shadow (technically called orographic precipitation) in the Antarctic Peninsula and its interaction with a mountain range covered in ice and snow. Orographic precipitation gives rise to the largest climatic and ecological gradients on Earth. Air ascending on the windward side of the mountain range expands and cools, condensing the water vapor it carries and producing heavy rain- or snow-fall. As the air descends on the leeward flank, the air warms and dries out, leaving little-to-no precipitation. This pattern of snowfall, caused by the interaction of winds and the landscape, is hypothesized to control the shape of the ice cap itself. The investigators hypothesize that feedbacks between precipitation and topography control ice flux and temperature, impacting basal conditions (frozen versus wet) and motion, which over long time scales can affect basal topography via erosion.The authors propose to investigate the feedbacks between orographically driven precipitation, ice dynamics, thermodynamics, and basal erosion and uplift over the northern Antarctic Peninsula by coupling an orographic precipitation model to the Parallel Ice Sheet Model (PISM). Using idealized and more realistic geometries, they will begin with a 2-D flow band model, which will be expanded into three dimensions to determine the strength of the feedbacks as a function of bedrock geometry and the intensity of the orographic precipitation gradient. The Antarctic Peninsula is targeted as the ideal case study, in the context of its rapid modern and future change as well as its deflation since the Last Glacial Maximum. The broader impacts of the work include the strengthening of predictive models by capturing feedbacks related to orographic precipitation not included in current models. This is likely to provide a more realistic assessment of the impacts of orographic precipitation in a regime of changing climate. The project will support an early career scientist and a female mid-career scientist and will support one PhD student, and provide summer research experience for one undergraduate student as an REU supplement. The project does not require field work in the Antarctic.