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预期的冰川消融加剧与多年冻土退化态势，对冰川-多年冻土-水文系统（glacier-permafrost-hydrology system）开展全面评估。当前学界对冰川与多年冻土对陆地水文过程的综合影响认知有限，这阻碍了冰冻圈变化（cryospheric changes）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（aquifers）补给水源，该区域尽管降水率相对较低，却分布有大面积湿地（wetlands）。本研究的具体目标包括：1）通过水文与地球化学野外实测，评估不连续多年冻土（discontinuous permafrost）覆盖流域内的冰川消融水文路径；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，以及耦合冰川物质平衡与下游水文过程的现有热质传递（heat- and mass transfer）模型，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盆地（Tanana River basin），采用自定义降尺度得到的5公里分辨率气候预测数据，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的控制机制进行量化分析。