CAREER: Linking Antarctic Cold Desert Groundwater to Thermokarst & Chemical Weathering in Partnership with the Geoscience UAV Academy

南极地下水驱动区域碳循环，加速永久冻土融化，形成南极地表特征。然而，在一个几乎被冰封的大陆上，地下水的范围、流量和过程却知之甚少。这项拟议的工作调查了南极寒冷沙漠景观中地下水、沉积物和冰之间的相互作用，以确定南极地下水流动的时间、地点和原因，以及它如何将南极冰冻沙漠从干燥和稳定演变为潮湿和动态。绘制南极近地表地下水的变化范围需要有能力在大范围内快速和反复地测量土壤湿度。该研究将通过无人机（UAV）测绘方法捕捉近地表地下水分布的变化。该项目将多种传感器与新型无人机技术相结合，提供比单独使用卫星观测更高分辨率和更频繁的南极地下水范围和组成评估。为了补充研究目标，PI将开发一个新的无人机夏季实地学校，即地球科学无人机学院，重点培训本科水平的无人机飞行员，使用尖端成像工具进行新的地球科学研究。研究和技术的整合将为学生在无人机相关行业和研究的职业生涯做好准备。该项目将为包括南极洲在内的干旱地区以及温带沙漠和旱地系统的土壤湿度测绘提供新的无人机工具和工作流程，并将培训学生研究飞行员，以应对下一代机载挑战。在南极麦克默多干谷（MDV）快速变化的永久冻土和湿地中，水道是基本的水文单元。尽管水道在MDV水文循环中的重要性及其对生物地球化学的影响，但人们对这些水道如何控制南极无冰区独特的盐水过程知之甚少。地下水的可用性和地球化学都塑造了南极微生物群落，将土壤地质和水文与碳循环和生态系统功能联系起来。本CAREER提案的目标是：1)绘制水迹图，确定地下水对MDV近地表环境影响的空间分布和季节大小，确定近地表地下水如何驱动多年冻土融化，增强化学风化和生物地球化学循环；2)建立无人机学院，培养地球科学专业学生利用无人机平台和遥感技术回答地球科学问题；3)为PI作为教师学者的发展提供形成性的步骤。无人机搭载的高光谱成像与现场土壤采样相结合，将确定MDV中代表性水迹的空中覆盖范围和淹没时间、水位和水预算。土壤湿度将通过近红外反射光谱测量，土壤和地下水的化学成分将通过离子色谱和土壤x射线荧光分析。沉积学和水文特性将通过对完整岩心样品的分析来确定。这些数据将用于测试关于水迹解决方案的起源和季节性湿地的水运动的相互竞争的假设。这项工作将提供对地下水来源、浅层地下水通量以及区域水文地质对向南大洋输出溶质和对地球碳收支中土壤/大气联系的影响的区域了解。无人机学院将1)在本科阶段提供全面的指导，说明无人机如何以及为什么可以促进地球科学的研究和学习；2)为无人机本科教育的夏季项目提供教育基础设施。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。

Antarctic groundwater drives the regional carbon cycle and can accelerate permafrost thaw shaping Antarctic surface features. However, groundwater extent, flow, and processes on a continent virtually locked in ice are poorly understood. The proposed work investigates the interplay between groundwater, sediment, and ice in Antarctica's cold desert landscape to determine when, where, and why Antarctic groundwater is flowing, and how it may evolve Antarctic frozen deserts from dry and stable to wet and dynamic. Mapping the changing extent of Antarctic near-surface groundwater requires the ability to measure soil moisture rapidly and repeatedly over large areas. The research will capture changes in near-surface groundwater distribution through an unmanned aerial vehicle (UAV) mapping approach. The project integrates a diverse range of sensors with new UAV technologies to provide a higher-resolution and more frequent assessment of Antarctic groundwater extent and composition than can be accomplished using satellite observations alone. To complement the research objectives, the PI will develop a new UAV summer field school, the Geosciences UAV Academy, focused on training undergraduate-level UAV pilots in conducting novel earth sciences research using cutting edge imaging tools. The integration of research and technology will prepare students for careers in UAV-related industries and research. The project will deliver new UAV tools and workflows for soil moisture mapping relevant to arid regions including Antarctica as well as temperate desert and dryland systems and will train student research pilots to tackle next generation airborne challenges. Water tracks are the basic hydrological unit that currently feeds the rapidly-changing permafrost and wetlands in the Antarctic McMurdo Dry Valleys (MDV). Despite the importance of water tracks in the MDV hydrologic cycle and their influence on biogeochemistry, little is known about how these water tracks control the unique brine processes operating in Antarctic ice-free areas. Both groundwater availability and geochemistry shape Antarctic microbial communities, connecting soil geology and hydrology to carbon cycling and ecosystem functioning. The objectives of this CAREER proposal are to 1) map water tracks to determine the spatial distribution and seasonal magnitude of groundwater impacts on the MDV near-surface environment to determine how near-surface groundwater drives permafrost thaw and enhances chemical weathering and biogeochemical cycling; 2) establish a UAV academy training earth sciences students to answer geoscience questions using drone-based platforms and remote sensing techniques; and 3) provide a formative step in the development of the PI as a teacher-scholar. UAV-borne hyperspectral imaging complemented with field soil sampling will determine the aerial extent and timing of inundation, water level, and water budget of representative water tracks in the MDV. Soil moisture will be measured via near-infrared reflectance spectroscopy while bulk chemistry of soils and groundwater will be analyzed via ion chromatography and soil x-ray fluorescence. Sedimentological and hydrological properties will be determined via analysis of intact core samples. These data will be used to test competing hypotheses regarding the origin of water track solutions and water movement through seasonal wetlands. The work will provide a regional understanding of groundwater sources, shallow groundwater flux, and the influence of regional hydrogeology on solute export to the Southern Ocean and on soil/atmosphere linkages in earth's carbon budget. The UAV school will 1) provide comprehensive instruction at the undergraduate level in both how and why UAVs can advance geoscience research and learning; and 2) provide educational infrastructure for an eventual self-sustaining summer program for undergraduate UAV education.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.