Collaborative research: What role do glaciers play in terrestrial sub-arctic hydrology?

The overall project assessed the linkages and controls of a subarctic glacier-permafrost hydrological system from a watershed-scale perspective using field measurements, remote sensing and numerical modeling. Jarvis Creek (634km2), which feeds the Delta and Tanana River in Interior Alaska, was studied as a proxy of the observed mountain glacier melting and permafrost degradation that has been documented across the Arctic region in recent decades. The specific objectives were to 1) assess the hydrologic fluxes (including streamflow source components), stores, pathways and the role of glacier wastage on watershed hydrology, through hydrologic and geochemical field measurements as well as numerical and statistical modeling; 2) quantify the effect of glaciers and permafrost on recent historical (1960-present) hydrologic fluxes and storage by combining remote sensing, field measurements of glacier mass balance, and hydrology with a heat- and mass transfer model, and 3) project the future hydrologic regime using custom-derived downscaled climate projections. The purpose of this Ground-Penetrating Radar (GPR) data set was to 1) quantify winter snow accumulation hydrological contributions separately from the glacierized and non-glacierized regions of Jarvis Watershed; and, 2) estimate total glacier ice volume of Jarvis Glacier and, based on yearly mass balance calculations, estimate total future glacier contribution changes from Jarvis Glacier to hydrological discharge. Winter accumulation ranged between 1.1 to 1.9 m SWE during each of the three seasons. Jarvis Glacier ice volume calculated from geophysical surveys and a manually digitized glacier outline during late season 2015 was 1.16 km^3 within an area of 8.82 km^2.本研究从流域尺度出发，采用野外观测、遥感技术与数值模拟相结合的方法，系统评估了亚北极冰川-冻土水文系统的相互作用与调控机制。选取阿拉斯加内陆地区注入三角洲河与塔纳纳河的贾维斯溪（流域面积634 km²）作为研究对象，其可作为近几十年来北极地区广泛观测记录的山地冰川消融与冻土退化现象的典型代用研究区。本研究的具体目标包括：1）通过水文与地球化学野外观测、数值模拟及统计分析手段，评估流域水文通量（含径流来源组分）、储水量、径流路径，以及冰川消融对流域水文过程的调控作用；2）结合遥感数据、冰川物质平衡野外观测、水文监测数据与热质传输模型，量化1960年至今的历史时段内，冰川与冻土对流域水文通量及储水量变化的影响；3）基于自主定制的降尺度气候预测数据，预估流域未来水文情势。本次探地雷达（Ground-Penetrating Radar, GPR）数据集的构建目的为：1）分别量化贾维斯流域冰川覆盖区与非冰川覆盖区的冬季积雪累积对水文过程的贡献；2）估算贾维斯冰川的总冰量，并结合年度物质平衡计算结果，预估贾维斯冰川未来对河道径流的总贡献变化。三个观测季的冬季积雪累积量介于1.1至1.9 m雪水当量（Snow Water Equivalent, SWE）之间。基于2015年季末的地球物理勘测数据与手动数字化的冰川轮廓线，贾维斯冰川在8.82 km²的覆盖面积内的总冰量为1.16 km³。