Predicting the future hydrology of Arctic watersheds dominated by thermokarst lakes

预测以热岩溶湖为主的北极流域的未来水文

• 批准号: RGPIN-2022-05347
• 负责人: Marsh, Philip
• 金额: $ 2.19万
• 依托单位: Wilfrid Laurier University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754912
• 关键词: Predicting; future; hydrology; Arctic; watersheds

Across extensive areas of the Arctic, watersheds are dominated by immense numbers of lakes that cover up to 50% of the land area and are linked together in complex streamflow networks. Where the permafrost is ice rich, many of these lakes are thermokarst lakes that exist in closed depressions formed by settlement of the ground during earlier episodes of thawing of ice rich permafrost. These lakes and their linked streamflow networks are entering a new stage of rapid and dramatic transformation as the Arctic warms and precipitation changes. Although climate is a strong driver of the hydrology of these networks, changes are also driven by interactions and feedbacks between changing vegetation, snowcover, ice rich permafrost thaw, and related ground surface subsidence. These changes are ongoing with lakes growing, shrinking, forming; and completely being removed from the landscape. Understanding ongoing changes to these systems is extremely difficult and beyond our current modelling ability. This is true for both changes expected to occur over the next decade, but also over the coming centuries as changes to vegetation and permafrost continue will continue long after the global temperature is stabilized, as the vegetation, permafrost and hydrology slowly equilibrate with the new climate. We require a new generation of predictive methods to develop scenarios of such long-term change and allow us to address key issues related to the importance of these systems to northern society, indigenous land claims regions, wildlife habitat, and climate feedbacks. This knowledge is essential to guide decisions needed to meet Canada's national and international agreements to limit greenhouse gas emissions to a level that will ensure the long-term preservation of these unique Arctic ecosystems. Our existing ability to predict the hydrology of these systems is extremely poor, including: hydrologic and climate data across the Arctic is extremely sparse, often of low quality, and not spatially distributed; the extreme spatial heterogeneity of these Arctic watersheds is poorly documented and challenges our ability to measure and model these systems; existing hydrologic models poorly represent this variability as they don't integrate surface and subsurface hydrology, lakes, vegetation, and permafrost; and ground thermal/hydrologic models do not include ground subsidence and feedbacks related to snow accumulation. This DG will address key issues in my overarching, multiple-decade Arctic research program that is focussed on addressing these knowledge and modelling limitations, with the overall goal to undertake transformative hydrological research to document past changes to the hydrology of the Canadian Arctic, provide realistic scenarios of the changes in Arctic hydrology under future climate change scenarios.

在北极广阔的地区，流域被大量的湖泊所主导，这些湖泊覆盖了多达50%的陆地面积，并以复杂的溪流网络连接在一起。在多年冻土富含冰的地方，这些湖泊中的许多都是热喀斯特湖泊，它们存在于封闭的凹陷中，这些凹陷是在富含冰的永久冻土融化的早期时期地面沉降形成的。随着北极变暖和降水的变化，这些湖泊及其相连的河流网络正在进入一个快速和戏剧性变化的新阶段。虽然气候是这些网络水文学的强大驱动力，但变化也受到变化的植被、积雪、富含冰的永久冻土融化和相关地面沉降之间的相互作用和反馈的推动。随着湖泊的生长、萎缩、形成和完全从景观中消失，这些变化正在进行中。理解这些系统正在发生的变化是极其困难的，超出了我们目前的建模能力。这不仅适用于预计在未来十年发生的变化，而且也适用于未来几个世纪，因为在全球气温稳定后很长一段时间内，植被和永久冻土的变化将继续下去，因为植被、永久冻土和水文学将慢慢与新的气候平衡。我们需要新一代预测方法来制定这种长期变化的情景，并使我们能够解决与这些系统对北方社会、土著土地主张地区、野生动物栖息地和气候反馈的重要性有关的关键问题。这些知识对于指导所需的决定至关重要，这些决定需要加拿大履行国家和国际协议，将温室气体排放量限制在确保长期保护这些独特的北极生态系统的水平。我们现有的预测这些系统的水文学的能力非常差，包括：整个北极的水文和气候数据极其稀少，通常质量不高，而且没有空间分布；这些北极分水岭的极端空间异质性记录得很少，挑战了我们测量和模拟这些系统的能力；现有的水文模型很难反映这种变异性，因为它们没有整合地表和地下水文学、湖泊、植被和永冻土；地面热/水文模型不包括地面沉降和与积雪相关的反馈。这一DG将解决我的总体、数十年的北极研究计划中的关键问题，该计划专注于解决这些知识和模型限制，总体目标是开展变革性的水文学研究，记录加拿大北极水文学过去的变化，提供未来气候变化情景下北极水文学变化的现实情景。