Remote Sensing and Modeling of Permafrost and Hydrology [1. Overview]

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：俄罗斯及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此前在多年冻土热状态（Thermal State of Permafrost, TSP）项目中启动的调查工作，并通过更新与扩展的合作模式推进研究。本项目聚焦并拓展了通过地球物理建模与遥感（卫星大地测量）手段开展的多年冻土与水文变化研究。 在TSP项目期间，本团队与上述俄方合作伙伴合作，筛选出大量现有钻孔用于潜在测量（候选站点）。其中多数钻孔的元数据可在国际冻土协会（International Permafrost Association, IPA）协调的全球冻土地面观测网（Global Terrestrial Network for Permafrost, GTN-P）网站上获取。未来将有更多站点补充至该网站，且计划在未来数年内新增一批钻孔。本次共筛选了位于俄罗斯、哈萨克斯坦与蒙古国的共计320个钻孔，评估其开展连续地热观测的可行性（详见附图）。这些钻孔涵盖了从连续多年冻土到零星多年冻土的所有类型，分布于平原与山地区域。 本次筛选的钻孔分为四类：① 在用站点：近期已开展常规观测且计划未来持续观测的站点；② 候选站点：可尽快安装长期观测设备的站点；③ 潜在站点：计划在本项目期间安装长期观测设备的站点；④ 历史站点：已有相关观测数据，但因各类原因目前无法开展观测的站点。 为规范本项目框架内的所有调查工作，团队制定了《多年冻土钻孔温度数据监测与报告手册》，以实现对获取数据的标准化采集、处理与解译工作。该规程提出了两类观测策略： 1. 策略1：在少量具有区域代表性的关键钻孔中开展长期高频（每小时至每日）连续观测（注：建议在15-20米深度范围内开展此类高频观测）； 2. 策略2：对其余可用的较深钻孔开展偶测或定期测量（若条件允许，建议每年开展一次或更频繁的测量）。 基于国际极地年-多年冻土热状态（International Polar Year-Thermal State of Permafrost, IPY-TSP）项目的成本考量，本项目最低配置建议采用搭载TMC-HD温度传感器的HOBO U12四通道外部数据采集器。同时，各参与方也可使用其他具备相似传感器性能的采集器或温感电缆（链）。 研究目标 本研究的目标是深入理解欧亚大陆北部与阿拉斯加地区多年冻土温度的时空（年际与年代际尺度）变异性与变化趋势，以及多年冻土物理变化（如融区与活动层）的特征，并据此建立更为可靠的预测模型，以实现对21世纪此类变化的科学投影。 本研究采用的数据来源包括：全球多年冻土温度网络地面观测数据集、国际地球参考框架（International Terrestrial Reference Frame, ITRF）组织的全球定位系统观测站点数据，以及各类卫星反演的物理参数数据集，例如地表温度、重力场变化、河流径流量与雪水当量等。 本研究的建模工作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。