Understanding the physical properties of Northern Greenland near-surface snow: A spatial variability study

该奖项将支持对从图勒到格陵兰顶峰的一条导线上的雪和积雪的物理性质和状态的调查。这项研究的“智力价值”与这样一个事实有关：格陵兰冰盖是冰冻圈对气候反应的重要指标，而且由于冰盖含有足够的水，如果冰盖全部融化，海平面将上升7米，因此了解冰盖的状态对科学家、政策制定者和整个社会至关重要。科学家们将伴随着再补给从Thule到Summit的穿越，并沿着一条横跨冰盖所有相(消融相、浸润相、渗滤相、干雪相)的路线，在降雪的1米深的雪坑和10米深的钻孔中对颗粒尺寸、密度和地层进行详细观察。将在现场应用的技术包括近红外摄影、钻孔光学地层学和中子散射探头。沿导线运行的探地雷达将提供地层数据，将在雪坑和钻孔中获得的地层信息联系起来。在导线开始和结束时获得的两个浅冰芯和雪样将被送回实验室，使用微型计算机断层扫描进行微结构检查，并使用光学和近红外摄影技术检查亮温。微结构结果将被用作辐射传输模型的输入，并且亮度温度将被用于验证模拟。这项研究有各种各样的“更广泛的影响”。该导线与1952-1955年的导线非常接近，当时对积雪和积雪性质的研究确立了冰川相的概念；将这些结果与本研究的结果进行比较，将为了解该地区自20世纪50年代中期以来发生的变化提供有价值的见解。地表和近地表积雪物理性质的空间变异性特征也可应用于遥感数据的解释，这对于绘制整个冰盖表面融化的地图至关重要。这项研究将邀请一名参加达特茅斯学院综合研究生教育和研究培训(IGERT)项目的研究生参加，并开发一系列以雪为主题的活动，这些活动是为蒙特郡科学博物馆三年级和四年级的四周课外项目设计的。这些活动将由达特茅斯大学的学生负责，他们经过博物馆工作人员的培训，进行以探究为基础的动手活动。主要研究人员都是职业生涯早期的科学家。

This award will support an investigation of the physical properties and state of snow and firn along a traverse from Thule to Summit Greenland. The 'Intellectual Merit' of the study relates to the fact that the Greenland Ice Sheet is an important indicator of the response of the cryosphere to climate and, since the ice sheet contains enough water to raise sea level by 7 meters if it were all to melt, understanding the state of the ice sheet is critically important to scientists, policy-makers and society at large. The scientists will accompany the resupply traverse from Thule to Summit, and make detailed observations of grain size, density and stratigraphy in 1 m deep snow pits and 10 m deep boreholes in firn along a route that crosses all the facies (ablation facies, soaked facies, percolation facies, dry snow facies) of the ice sheet. Techniques to be applied in the field include near infra-red photography, borehole optical stratigraphy and a neutron-scattering probe. A ground-penetrating radar operated along the traverse will provide stratigraphic data that links the stratigraphic information obtained in the snow pits and boreholes. Two shallow ice cores obtained at the beginning and end of the traverse, and snow samples, will be returned to the laboratory for examination of microstructure using micro-computed tomography and brightness temperature using optical and near-infra-red photography. The microstructure results will be used as input to a radiative transfer model and the brightness temperature will be used for validation of the simulations. The study has a variety of 'Broader Impacts'. The traverse lies very close to traverses made in 1952-55 when studies of snow and firn properties established the concept of glaciers facies; a comparison of those results with those of this study will provide valuable insights into changes that have occurred in this region since the mid-1950s. The characterization of the spatial variability of the physical properties of surface and near-surface snow also has application to the interpretation of remote sensing data, which are essential to mapping surface melting across the entire ice sheet. The study will involve a graduate student participant in the Dartmouth College Integrated Graduate Education and Research Traineeship (IGERT) program - 'Polar Environmental Change' - and develop a series of snow-science-themed activities designed for a four week after-school program for grades 3 and 4 at the Montshire Museum of Science. The activities will be run by Dartmouth students trained by museum staff in inquiry-based, hands-on activities. The principal investigators are both early-career scientists.