Collaborative Research: The role of capillaries in the Arctic hydrologic system

合作研究：毛细血管在北极水文系统中的作用

• 批准号: 2234117
• 负责人: Anna Liljedahl
• 金额: $ 30.24万
• 依托单位: Woodwell Climate Research Center, Inc.
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2234117&HistoricalAwards=false
• 关键词: Collaborative; Research; role; capillaries; Arctic

Thawing ice-rich permafrost is transforming Arctic tundra landscapes from being relatively flat and evenly moist into a mosaic of dry mounds and narrow ponds. As thaw progresses, a well-drained landscape with a maze of tiny surface drainages may form. This dense network of small channels represents the capillaries of the Arctic hydrologic system and serves as the originators of the water that feeds large rivers. An expanding capillary hydrologic system may change habitat for wildlife due to an overall drying of the tundra landscape, increased river runoff, and through more nutrients exported from terrestrial to aquatic environments. Further, an expanding capillary hydrological network that is identifiable from sub-meter resolution satellite imagery can serve as an indicator of ice-rich permafrost thaw and, therefore, warn of hazard to infrastructure. The development and expansion of a surface drainage system may also decrease the likelihood of moss to thrive, which results in loss of a vegetation cover that effectively cools the ground and preserves the upper permafrost from thawing. The project will produce a pan-Arctic map of the capillary hydrological system and in selected areas, advance understanding of how the capillary system has changed over time. The geospatial products will be made publicly accessible on the Permafrost Discovery Gateway to enable discovery and knowledge-generation by scientists, stakeholders, and the public.Field observations have shown that runoff from many Arctic rivers has increased in recent decades. Simultaneously, several studies have documented ice wedge degradation across the Arctic, and a handful of local field and remote sensing studies in Northern Alaska have shown that the capillary hydrologic system is expanding due to partial melting of ice wedges. This project aims to map the extent of the capillary hydrologic system across the pan-Arctic tundra and assess the role of the capillary system in generating water flow and lateral carbon flux to large rivers. Graph analysis techniques applied to the pan-Arctic ice-wedge polygon map, as well as deep learning/AI algorithms trained to detect a capillary system from very high spatial resolution satellite imagery, will allow the network of ice wedges and the capillary hydrologic system to be mapped across the Arctic tundra. Field measurements in northern and northwestern Alaska will include geochemical water sampling, coring of permafrost to assess ice-wedge status (degradation or stabilization), and ground-truthing for the remote sensing hydrologic network analyses. This new information will inform a numerical hydrology model to quantify how important the capillaries are in contributing freshwater and carbon flows to the Arctic Ocean. Earlier hydrological model experiments have shown that the formation of connected troughs-networks can double the runoff from the landscape even if the rain and snowfall amounts remain unchanged. The pan-Arctic map of hydrological capillaries will support a first study on how important sub-meter wide channels are to large Arctic river runoff.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.

融化的富含冰块的永久冻土正在将北极苔原的景观从相对平坦且均匀的潮湿转变为干丘和狭窄的池塘的马赛克。随着融化的进展，可能会形成带有微小表面排水迷宫的排水良好的景观。这个小通道的密集网络代表了北极水文系统的毛细血管，并充当供大河流的水的发起者。由于苔原景观的整体干燥，增加的河流径流以及通过从陆地到水生环境出口的更多营养，扩大的毛细血管水文系统可能会改变野生动植物的栖息地。此外，可以从亚米分辨率卫星图像中识别出的扩展毛细血管水文网络可以作为富含冰块的永久冻结融化的指标，因此可以警告危害基础设施。表面排水系统的发展和扩展也可能降低苔藓的可能性，从而导致植被覆盖的损失，从而有效地冷却地面并保留上层永久冻土，使其无法解冻。该项目将生成毛细管水文系统和选定区域的泛北极地图，并提高了解毛细管系统如何随着时间而变化的理解。地理空间产品将在多年冻土发现门户上公开访问，以实现科学家，利益相关者和公众的发现和知识产生。场外观察表明，最近几十年来，许多北极河的径流都在增加。同时，几项研究记录了北极的冰楔降解，阿拉斯加北部的少数本地田间和遥感研究表明，由于冰楔的部分融化，毛细血管水文系统正在扩大。该项目旨在绘制跨二极苔原的毛细血管水文系统的范围，并评估毛细管系统在产生水流和向大河流的侧碳通量中的作用。应用于泛二极的冰对边缘多边形图以及经过深入学习/AI算法的图形分析技术，可以从非常高的空间分辨率卫星图像中检测到毛细管系统，将允许冰楔形网络和毛细血管水平系统在弧形苔原上映射。阿拉斯加北部和西北部的现场测量将包括地球化学水采样，多年冻土的加芯，以评估冰对木质状态（降解或稳定）以及用于遥感水文网络分析的地面潮流。这些新信息将为数值水文模型提供信息，以量化毛细血管在贡献淡水和碳流向北极海洋方面的重要性。早期的水文模型实验表明，即使雨水和降雪数量保持不变，连接的槽网络的形成也可以使景观的径流增加一倍。水文毛细血管的泛极图将支持首次研究，该奖项反映了NSF的法定任务，该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力优点和更广泛影响的审查标准来评估值得支持的。