Glacier's effects in terrestrial sub-Arctic hydrology, 2014-2017

This project will develop a comprehensive assessment of the glacier-permafrost-hydrology system in light of anticipated increases in glacier wastage and permafrost degradation with climate warming. Current limited understanding of the integrated effects of glaciers and permafrost on terrestrial hydrology inhibits quantification of the impact of cryospheric changes on arctic water resources. Glaciers in permafrost landscapes feed and recharge aquifers in otherwise semi-arid lowlands, which despite relatively low precipitation rates, contain extensive wetlands. The specific objectives of this study are to 1) assess the hydrologic pathways of glacier wastage within a watershed underlain by discontinuous permafrost through hydrologic and geochemical field measurements, 2) quantify the effect of glaciers and permafrost on recent historical (1960-present) hydrologic fluxes and storage by combining glacier mass balance, hydrologic, and geochemical field measurements with an existing heat- and mass transfer model that couples glacier mass balance to downstream hydrology, and 3) project the future hydrologic regime using custom-derived downscaled climate projections (5 km) for the Tanana River basin, Alaska. The major products of the project will include a quantification of the controls that govern the hydrologic processes in glacier- and permafrost affected watersheds.本项目将针对气候变暖背景下冰川消融与多年冻土（permafrost）退化加剧的趋势，对冰川-多年冻土-水文系统开展全面评估。当前学界对冰川与多年冻土对陆地水文的综合影响认知不足，这阻碍了冰冻圈（cryospheric）变化对北极水资源影响的量化研究。多年冻土区的冰川可为原本半干旱低地的含水层提供补给与补水，这些区域虽降水相对稀少，却分布着大面积湿地。本项目的具体研究目标为：1）通过水文与地球化学野外实测手段，评估不连续多年冻土区流域内冰川消融的水文路径；2）结合冰川物质平衡（glacier mass balance）、水文与地球化学野外实测数据，以及一套将冰川物质平衡与下游水文过程耦合的现有热质传输模型（heat- and mass transfer model），量化冰川与多年冻土对近期（1960年至今）水文通量与储水量的影响；3）针对阿拉斯加塔纳纳河流域（Tanana River basin），采用定制化降尺度得到的5公里分辨率气候预测数据（downscaled climate projections），预估未来水文情势。本项目的主要成果将包括对冰川与多年冻土影响流域内水文过程主控因子的量化分析。