Remote Sensing and Modeling of Permafrost and Hydrology [3. Permafrost Models: Alaska]

Study Sites Permafrost Freshwater Interactions Alaska, Canada, Russia Permafrost Observatories Thermal state of permafrost in Russia and Central Asia Permafrost Freshwater Interactions Project continues investigations began during the Thermal State of Permafrost (TSP) Project with renewed and expanded collaboration. Our efforts focus and expand on permafrost and hydrology changes through geophysical modeling and remote sensing (satellite geodesy). During TSP in cooperation with above mentioned Russian partners a large number of existing boreholes have been identified for possible measurements (candidate sites). Many of these have metadata files on the IPA coordinated GTN-P website. Additional sites will be added to the web site. New boreholes over the next several years are planned. A total of 320 boreholes, located in Russia, Kazakhstan, and Mongolia were considered from the point of view of possibility for continuous geothermal observations (see Figure). Boreholes cover all types of permafrost, from continuous to sporadic, both on the plains and in the mountains. Active (sites where regular observations were carried out recently and are intended to continue in the future), candidate (where equipment for long-term observations can be installed soon), potential (equipment for long-term observation is planned to be installed during the project) and historical (there are some existing data but now these sites are unavailable for observations for different reasons) boreholes were selected. In order to standardize all investigations within the framework of the Project the "Manual for monitoring and reporting temperature data in permafrost boreholes" was developed. It allows better standardized collection, handling and interpretation of obtained data. In the Protocol two types of observation strategies are proposed: Type 1: Long-term high-frequency (hourly to daily) continuous observations in the limited number of key boreholes, which are representative of a given regions (note: these more frequent observations are desirable to depths of 15-20 meters); Type 2: Occasional or periodical measurements in the other available and deeper boreholes (if possible annual or more frequently). As a minimum, and based primarily on cost considerations for the IPY-TSP program, the use of HOBO U12 4-External Channel Data Loggerswith temperature sensors TMC-HD are proposed. At the same time, individual participants can employ other types of loggers and/or thermal cables (chains) with similar sensor characteristics. Research Goals The goal of our research is to obtain a deeper understanding of the temporal (interannual and decadal time scales) and spatial (north to south and west to east) variability and trends in the permafrost temperatures and physical changes (such as talik and the active layer) in the North of Eurasia and Alaska to develop more reliable predictive capabilities for the projection of these changes into the 21st century. We are employing ground datasets from the global permafrost temperature networks, global positioning system sites of the International Terrestrial Reference Frame organization, together with satellite-derived datasets of physical parameters such as land-surface temperature, gravity field changes, river runoff and snow water equivalent to name a few. Our modeling efforts employ the Geophysical Institute Permafrost Models (GIPL) and Geophysical Inverse Potential Field Theory.研究站点 多年冻土-淡水相互作用 阿拉斯加、加拿大、俄罗斯 多年冻土观测站：俄罗斯与中亚地区多年冻土热状态 多年冻土-淡水相互作用项目延续了“多年冻土热状态（Thermal State of Permafrost, TSP）”项目的前期研究工作，并通过拓展合作规模与领域深化相关研究。本项目依托地球物理建模与遥感（卫星大地测量）技术，聚焦并拓展多年冻土与水文变化的研究。 在“多年冻土热状态（TSP）”项目实施期间，我们与前述俄罗斯合作方协作，甄别出大量可开展潜在测量的现有钻孔（候选站点）。其中多数站点的元数据可在国际极地年（International Polar Year, IPY）协调的全球冻土观测网络（Global Terrestrial Network for Permafrost, GTN-P）官方网站查询。后续将有更多站点补充至该网站，未来数年内还计划钻探新的钻孔。我们共遴选了位于俄罗斯、哈萨克斯坦与蒙古国的共计320个钻孔，以评估其开展连续地热观测的可行性（详见附图）。这些钻孔覆盖了从连续多年冻土到零星多年冻土的全部类型，涵盖平原与山地两种地貌。我们选取了四类钻孔：活跃钻孔（近期已开展常规观测且计划未来持续进行）、候选钻孔（可尽快安装长期观测设备）、潜在钻孔（计划在本项目期间安装长期观测设备）与历史钻孔（现存部分观测数据，但因各类原因目前无法开展观测）。 为统一本项目框架内的所有研究工作，我们编制了《多年冻土钻孔温度数据监测与报告手册》，以实现观测数据的标准化采集、处理与解译。该规程提出了两类观测策略： 类型1：在代表特定区域的少量关键钻孔中开展长期高频（每小时至每日）连续观测（注：此类高频观测建议覆盖15~20米深度）； 类型2：在其余可用的较深钻孔中开展偶测或定期测量（若条件允许可每年开展一次或更频繁的测量）。 基于IPY-TSP项目的成本考量，本项目建议优先使用搭载TMC-HD温度传感器的HOBO U12四通道数据记录仪。同时，各参与方也可采用其他具备相似传感器特性的记录仪或热感电缆（链）。 研究目标 本研究旨在深入理解欧亚大陆北部与阿拉斯加地区多年冻土温度及物理变化（如融区与活动层）的时空（年际、年代际时间尺度，以及南北、东西空间维度）变异性与变化趋势，进而为21世纪该类变化的预测提供更可靠的支撑能力。我们将整合全球多年冻土温度网络地面观测数据集、国际地面参考框架（International Terrestrial Reference Frame, ITRF）组织的全球定位系统站点数据，以及卫星反演的多项物理参数数据集，包括地表温度、重力场变化、河流径流与雪水当量等。本项目的建模工作将采用地球物理研究所多年冻土模型（Geophysical Institute Permafrost Models, GIPL）与地球物理反演势场理论。