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，为村庄和工业提供重要的鱼类和野生动物栖息地和供水，但也与冻土(永久冻土)及其储存的碳相互作用。这些湖泊中的大多数被称为热岩溶，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。热岩溶湖泊的动态性质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(DTLB)。热岩溶湖泊和DTLB总共覆盖了北极80%的低地地区，因此了解它们对正在进行的气候变化的反应对于沿海平原环境评估至关重要。灾难性的湖泊排水和随之而来的DTLB生态系统演替长期以来一直引起关注永久冻土、植被和碳储存的科学家的兴趣。然而，人们对预测湖泊何时何地排干以及下游洪水的规模和影响的关注较少。到目前为止，北极水文学中也忽视了一个相关的过程，即现有DTLB引发的雪坝溃决洪水。雪坝溃决产生的洪水可能有助于解释许多北极河流异常巨大的洪峰，对于未来的石油开发以及扩大沿海平原地区道路和管道的需要，将越来越重要。这项关于灾难性湖泊排水的研究对于提高我们对多年冻土和水文过程的理解，识别洪水和地面稳定性的危害，以及预测未来的植被、陆地和水生生境以及碳储存动态具有重要意义。结合遥感、野外观测和湖泊排水实验，旨在了解DTLB形成的原因和后果，以及它们与北极系统其他组成部分的更广泛的反馈。这项研究收集的数据将用于未来的模型开发，以加强对北极地区气候变化的水文灾害和景观反应的预测能力。DTLB时间序列的空间换时间比较提供了将过程尺度联系起来的概念框架。该项目产生的新概念模型对许多利益攸关方和土著村庄很重要，在这些村庄，水的获取、栖息地缓解和避免灾害是优先事项。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海岸平原上的工业、土地管理者和自给自足用户的利益。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.