Remote Sensing and Modeling of Permafrost and Hydrology [4. Remote Sensing Data: GRACE]

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热状态多年冻土（TSP）项目期间启动的研究，并开展了更新与拓展性合作。我们的工作通过地球物理建模与遥感（卫星大地测量学），聚焦并拓展对多年冻土及水文变化的研究。
在TSP项目期间，与上述俄罗斯合作伙伴合作，确定了大量现有钻孔作为潜在测量站点（候选站点）。其中许多钻孔的元数据文件可在国际多年冻土协会（IPA）协调的全球多年冻土观测网（GTN-P）网站上获取。更多站点将被添加至该网站。未来数年计划新增钻孔。共考虑了俄罗斯、哈萨克斯坦及蒙古境内的320个钻孔，评估其进行连续地热观测的可行性（见图）。这些钻孔覆盖了平原与山区的各类多年冻土，从连续多年冻土到零星多年冻土均有涉及。选定的钻孔包括活跃站点（近期已开展常规观测且计划未来持续进行）、候选站点（可近期安装长期观测设备）、潜在站点（计划在项目期间安装长期观测设备）及历史站点（存在部分现有数据，但因各种原因目前无法进行观测）。
为规范项目框架内的所有研究工作，制定了《多年冻土钻孔温度数据监测与报告手册》。该手册有助于实现数据收集、处理及解释的更高标准化水平。协议中提出两种观测策略：类型1：在有限数量的代表性关键钻孔中进行长期高频（小时至日尺度）连续观测（注：此类高频观测建议深度达15-20米）；类型2：在其他可用的更深钻孔中进行不定期或定期测量（尽可能每年或更频繁）。

研究目标
本研究旨在深入理解欧亚大陆北部及阿拉斯加地区多年冻土温度及物理变化（如融区和活动层）的时间（年际及年代际尺度）与空间（南北向及东西向）变异性及趋势，以提升对这些变化在21世纪演变的可靠预测能力。我们采用了来自全球多年冻土温度网络的地面数据集、国际陆地参考框架组织的全球定位系统站点数据，以及卫星衍生的物理参数数据集（如地表温度、重力场变化、河流径流及雪水当量等）。建模工作采用地球物理研究所多年冻土模型（GIPL）及地球物理反演势场理论。