Collaborative Research: Present and future contribution of glacial runoff to freshwater discharge into the Gulf of Alaska

流入阿拉斯加湾(GOA)的淡水受到冰川径流的强烈影响，因为大约五分之一的流域被冰川覆盖。在过去几十年中，果阿冰川普遍变薄和消退，因此，随着冰雪的释放，储存在冰川中的降水增加了流向阿拉斯加湾的水流和淡水的流入。流入果阿的冰川对气候变暖高度敏感，预计质量损失率将会增加。据推测，冰川径流量最初将随着损耗的加速增加50%以上，但随后将达到一个转折点，当冰川缩小并部分消失时，径流量将减少。因此，由于冰川消融导致的水文循环的变化比该地区水收支的任何其他组成部分的预期变化要大得多。研究将量化这些径流变化。冰川径流模型用于模拟目前流入阿拉斯加湾的冰川径流的大小和时间，并预测阿拉斯加湾沿线的冰川径流到2100年将如何变化，以响应阿拉斯加未来的气候情景，该情景被一个高分辨率的区域气候模型缩小。此外，还评估了与冰川径流预测变化有关的流入淡水和海洋生态系统的生物地球化学通量的潜在变化。结果提供了区域尺度的冰川径流变化估计及其对GOA生物地球化学通量的相关影响。开发了一种可用于评估冰川径流变化和水文临界点的建模策略。在其他冰川化严重的地区。此外，我们开发的缩小尺度的气候情景将可用于其他影响研究。结果的可视化产品提供给门登霍尔冰川游客中心，该中心每年约有35万人参观。

Freshwater influx to the Gulf of Alaska (GOA) is strongly influenced by glacier runoff as roughly one fifth of its drainage basin is covered by glacier ice. During the last decades GOA glaciers have generally thinned and retreated and hence precipitation stored in the glaciers as snow and ice has been released augmenting streamflow and freshwater influx to the Gulf of Alaska. Glaciers draining to the GOA are highly sensitive to climate warming and mass loss rates are expected to increase. It is hypothesized that runoff from glaciers will initially increase by more than 50% as wastage accelerates, but then will reach a turning point upon which runoff will decrease as the glaciers shrink and partly disappear. Hence, the changes in the hydrological cycles due to glacier wastage are substantially larger than expected changes in any other component of the water budget in this region.The research will quantify these changes in runoff. A glacier runoff model is used to simulate the current magnitude and timing of runoff from glaciers that drain to the Gulf of Alaska and project how glacial runoff along the Gulf of Alaska will change by 2100 in response to future climate scenarios in Alaska downscaled by a high resolution regional climate model. Further, potential changes to the biogeochemical fluxes into freshwater and marine ecosystems associated with the projected changes in glacier runoff are assessed. Results provide regional scale estimates of glacier runoff changes and associated impacts on biogeochemical fluxes for the GOA. A modeling strategy is developed that can be used to evaluate glacier runoff changes and hydrologic ?tipping points? in other heavily glacierized regions. Moreover, the downscaled climate scenarios we develop will be available for other impact studies. Visualization products of the results are made available to the Mendenhall Glacier visitor center, which is visited by approximately 350,000 people each year.