EAR-Climate: Acquisition of hydrometric equipment to support undergraduate training and research on glacier lake outburst floods in southeast Alaska

每年夏天，由于气候变暖，冰川都会融化，并在数年内退缩，冰川融水的化学性质也会发生变化。研究冰川释放的融水的物理和化学特征是很重要的，因为它直接影响下游湖泊、溪流和沿海海洋区域的质量。阿拉斯加东南部的沿海山脉正经历着地球上冰川融化速度最快的地区。随着冰川的萎缩，它们留下了新形成的景观和水体，如冰川前的湖泊（前冰川湖）和冰川边缘被冰川冰阻塞的湖泊（冰川堰塞湖）。这样的湖泊可以捕获沉积物、营养物质、碳和其他元素，阻止它们向下游移动。此外，如果冰坝坍塌，冰川筑坝的湖泊可能会突然大量泄洪，造成洪水危险，并向下游输送大量沉积物和溶解的化学物质。随着阿拉斯加数以千计的冰川正在消退，对冰川化流域的持续变化进行表征和量化，并更好地了解其生态影响，这一点至关重要。我们将利用本项目获得的声波多普勒测速仪和其他设备，跟踪阿拉斯加东南部一个冰川堰塞湖和一个前冰川湖进出的水和沉积物的数量和质量。为此，我们将让阿拉斯加东南大学（University of Alaska Southeast）和当地高中的本科生参与进来，并对他们进行培训，帮助下一代地球科学家掌握研究冰川变化、水文动力学、地球表面过程和自然灾害所需的技能和工具。气候变化导致阿拉斯加海岸山脉的冰川以地球上最快的速度消退。冰川质量损失的增加导致了(1)原冰湖和(2)冰川堰塞湖的增长，前者可以极大地改变流域的沉积物和化学物质输出，后者可以产生危险的冰湖溃决洪水（GLOFs），并向下游生态系统释放大量生物地球化学元素和沉积物。了解这些与冰川相关的湖泊中碳、水、沉积物和金属（如汞）的储存和释放，对于解释冰川退缩和随之而来的景观变化如何影响当前和未来的化学和沉积物通量非常重要。随着气候变暖的持续和冰川的进一步减少，冰川流域不断变化的物理和化学输出将对接收水生生态系统产生影响，包括食物网结构和生产力、污染物的可得性、沿海沉积物中的有机碳埋藏、向大气排放的二氧化碳以及沿海海洋酸化的季节性时间和强度。在这个项目中，我们将通过在阿拉斯加朱诺冰川化的门登霍尔流域获取多普勒测速仪、水质探空仪和多探头水质仪来监测阿拉斯加东南部冰川变化的水文影响。这些水文测量仪器将用于阿拉斯加东南大学（University of Alaska Southeast）的课堂实验和研究助理奖学金，以及当地高中生的培训。阿拉斯加东南大学是一所小型的阿拉斯加本土服务本科大学。这些工具将使我们能够进一步发展一项研究计划，旨在了解冰川融化和全球变暖对阿拉斯加东南部高产沿海流域沉积物和化学品出口的动态和后果。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

As glaciers melt each summer and recede over the years due to the warming climate, the chemical nature of their meltwater changes. Studying the physical and chemical characteristics of the meltwater released from glaciers is important because it directly affects the quality of downstream lakes, streams, and coastal marine zones. The Coastal Mountains of southeast Alaska are experiencing some of the highest glacial melt rates on Earth. As the glaciers shrink, they leave behind newly formed landscapes and waterbodies such as lakes collecting water in front of the glacier (proglacial lakes) and lakes on the edges of glaciers that are dammed by the glacier ice (glacially dammed lakes). Such lakes can trap sediment, nutrients, carbon, and other elements, preventing them from moving downstream. Additionally, glacially dammed lakes can suddenly release massive outbursts of water if their ice dam fails, creating flooding hazards and sending a surge of sediment and dissolved chemicals downstream. With thousands of glaciers currently receding in Alaska, it is critical to characterize and quantify the ongoing changes in glacierized watersheds and to better understand their ecological impacts. We will track the quantity and quality of water and sediment moving through and out of a glacially dammed lake and a proglacial lake in southeast Alaska using the acoustic doppler velocimeter and other equipment acquired through this project. In doing so, we will involve and train undergraduate students from the University of Alaska Southeast and the local high school, helping to equip the next generation of earth scientists with the skills and tools they need to address glacier change, hydrologic dynamics, Earth surface processes, and natural hazards.Climate change has triggered glaciers in the Coastal Mountain of Alaska to recede at some of the highest rates on Earth. Increased glacier mass loss is causing the growth of (1) proglacial lakes that can dramatically alter sediment and chemical export from watersheds and of (2) glacially-dammed lakes, which can produce hazardous glacial lake outburst floods (GLOFs) and release a large pulse of biogeochemical elements and sediment to downstream ecosystems. Understanding the storage and release of carbon, water, sediment, and metals such as mercury in and through these glacier-associated lakes is important for explaining how glacier retreat and ensuing landscape change will affect current and future chemical and sediment fluxes. As warming continues and glaciers further diminish, the changing physical and chemical outputs from glaciated watersheds will have implications for recipient aquatic ecosystems, including food web structure and productivity, availability of contaminants, organic carbon burial in coastal sediments, CO2 outgassing to the atmosphere, and the seasonal timing and intensity of coastal ocean acidification. In this project, we will monitor the hydrometric impacts of glacial change in southeast Alaska by acquiring an Accoustic Doppler Velocity meter, water quality sondes, and a multi-probe water quality meter for use in the glacierized Mendenhall watershed in Juneau, Alaska. The hydrometric instruments will be used to train undergraduate students through class labs and research assistantships at the University of Alaska Southeast, which is a small, Alaska-native serving, undergraduate university, and to engage local high school students. The instruments will allow us to further develop a research program aimed at understanding the dynamics and consequences of glacier melt and GLOFs on sediment and chemical export to the highly productive coastal watersheds of southeast Alaska.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.