Collaborative Research: Causes and Consequences of Catastrophic Thermokarst Lake Drainage in an Evolving Arctic System

湖泊是北极沿海平原上丰富的特征，为鱼类和野生动物提供了重要的栖息地，为村庄和工业提供了水源，但也与冻土（永久冻土）及其储存的碳相互作用。这些湖泊大多被称为“热岩溶”，因为它们形成于富含冰的永久冻土中，并随着时间的推移逐渐扩大。热岩溶湖的动态性也使它们容易发生灾难性的排水和突然转变为湿地，称为排水热岩溶湖盆地（dtlb）。热岩溶湖和dtlb共同覆盖了北极低地地区的80%，因此了解它们对持续气候变化的响应对于沿海平原环境评估至关重要。长期以来，dtlb灾难性的湖泊排水和随后的生态系统演替一直吸引着关注永久冻土、植被和碳储存的科学家。然而，人们对预测湖泊何时何地干涸以及下游洪水的规模和影响的关注较少。一个相关的过程，即现有dtlb的雪坝溃决洪水，迄今在北极水文学中也被忽视了。雪坝溃决产生的洪水可能有助于解释许多北极河流异常大的洪峰，这对未来的石油开发以及在沿海平原地区扩建道路和管道的需要将越来越重要。对灾难性湖泊排水的研究有助于提高我们对多年冻土和水文过程的认识；识别洪水和地面稳定危害；预测未来的植被，陆地和水生栖息地，以及碳储存动态。遥感、野外观测和湖泊排水试验相结合的目的是了解DTLB形成的原因和后果及其与北极系统其他组成部分的更广泛反馈。本研究收集的数据将用于未来的模型开发，以提高北极水文灾害和景观对气候变化反应的预测能力。DTLB时间序列的时空比较为连接过程尺度提供了概念框架。该项目产生的新概念模式对一些利益攸关方和土著村庄非常重要，因为在这些地方，水的获取、栖息地的缓解和避免危害是优先事项。从这项研究中获得的对危害和环境过程的理解将促进阿拉斯加北部北极沿海平原的工业、土地管理者和生存用户的利益。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。

Lakes are abundant features on coastal plains of the Arctic, providing important fish and wildlife habitat and water supply for villages and industry, but also interact with frozen ground (permafrost) and the carbon it stores. Most of these lakes are termed "thermokarst" because they form in ice-rich permafrost and gradually expand over time. The dynamic nature of thermokarst lakes also makes them prone to catastrophic drainage and abrupt conversion to wetlands, called drained thermokarst lake basins (DTLBs). Together, thermokarst lakes and DTLBs cover up to 80% of arctic lowland regions, making understanding their response to ongoing climate change essential for coastal plain environmental assessment. Catastrophic lake drainage and subsequent ecosystem succession in DTLBs has long intrigued scientists concerned with permafrost, vegetation, and carbon storage. Less attention however has been devoted toward predicting where and when lakes will drain and the magnitude and impacts of downstream flooding. A related process, snow-dam outburst floods from existing DTLBs, has also been overlooked so far in arctic hydrology. Floods generated from snow-dam outburst may help explain abnormally large flood peaks in many arctic rivers and will be increasingly important to consider for future petroleum development and the need to expand roads and pipeline through coastal plain terrain. This research on catastrophic lake drainage is relevant to improving our understanding of permafrost and hydrological processes; identifying flood and ground stability hazards; and predicting future vegetation, terrestrial and aquatic habitat, and carbon storage dynamics.A combination of remote sensing, field observations, and a lake-drainage experiment are targeted at understanding the causes and consequences of DTLB formation and their broader feedbacks with other arctic system components. Data collected in this study will feed into future model development to enhance predictive capacity of hydrologic hazards and landscape responses to climate change in the Arctic. Space-for-time comparison of DTLB chronosequences provides the conceptual framework for linking process scales. The new conceptual model emerging from this project is important for a number of stakeholders and native villages, where water access, habitat mitigation, and hazard avoidance are a priority. The understanding of hazards and environmental processes gained from this research will advance the interests of industry, land managers, and subsistence users on the Arctic Coastal Plain of northern 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.