Daily Averages of Aerosol Properties in Summit, Greenland

The collaborative team will take advantage of the currently funded Greenland Inland Traverse (GrIT) traveling between Thule and Summit Greenland to access a spatially diverse area of the GIS in order to better understand albedo variability and the snow properties that influence albedo. The GrIT route offers a unique opportunity to study a wide range of snow accumulation zones (i.e. the ablation zone, soaked snow zone, the percolation zone and the dry snow zone) across Greenland, which are expected to have a broad range of albedo values as well as significant variability in snow physical properties and concentrations of light absorbing compounds (i.e. dust, elemental carbon, and brown carbon). The project's field component will take place over two seasons during the spring of 2013 and 2014. The approach will include stopping along the traverse to collect coincident daily measurements of snow spectral albedo, snow physical properties (i.e. specific surface area, density), surface snow light absorption properties (i.e. wavelength dependent absorption of water soluble compounds and particulates), and the concentrations of trace elements, organic, and elemental carbon. Additionally, the temporal evolution of spectral albedo will be monitored continuously during the sunlit months using autonomous stations deployed along the traverse route to track seasonal variations of snow albedo and to help attribute these variations to the physical and chemical composition of the snow. The results of this project will yield a unique data set characterizing the temporal and spatial variability of surface albedo as well as the physical and chemical properties of Greenland snow, which are broadly useful to both modeling, ice mass balance, and remote sensing communities. Conference presentations, rapid publication of results, and most importantly close collaboration with modelers, (i.e. through work with the CESM PCWG) will ensure that this knowledge is used to improve process parameterizations in predictive global climate models. The team will also build on international collaborations begun in the Dartmouth IGERT program, including a week-long ambassadorship to Nuuk by co-PI Polashenski including lectures at the college and Katuuaq cultural center. Graduate, undergraduate, and high school student training will also be included in the project.

本合作团队将依托当前获得资助的、往返于图勒（Thule）与格陵兰冰盖最高点（Summit Greenland）的格陵兰内陆巡测计划（Greenland Inland Traverse, GrIT），造访格陵兰冰盖（Greenland Ice Sheet，原文缩写GIS）空间分布多样的区域，以深入解析反照率（albedo）变异性及其影响因素——积雪属性。格陵兰内陆巡测路线为研究格陵兰岛广泛分布的积雪积累带提供了独特契机，这些区域涵盖消融带、湿雪带、渗流带与干雪带，预计其反照率取值跨度范围广泛，同时积雪物理属性与吸光化合物（即尘埃、元素碳（elemental carbon）、棕碳（brown carbon））的浓度也存在显著变异性。本项目的野外工作将分两个阶段开展，实施时段为2013年与2014年的春季。野外观测方案将包括沿巡测路线停靠，同步开展每日积雪光谱反照率（spectral albedo）、积雪物理属性（即比表面积（specific surface area）、密度）、表层积雪光吸收特性（即水溶性化合物与颗粒物的波长依赖性吸收），以及微量元素、有机碳与元素碳浓度的测量。此外，团队将在日照月份沿巡测路线部署自动监测站，对光谱反照率的时间演化特征进行连续监测，以追踪积雪反照率的季节变化，并助力厘清这些变化与积雪物理化学组成之间的因果关联。本项目的研究成果将形成一套独特的数据集，可表征格陵兰积雪表层反照率的时空变异性，以及积雪的物理与化学属性，该数据集对建模、冰量平衡与遥感领域均具有广泛的应用价值。通过学术会议报告、研究成果快速发表，以及最为关键的与建模人员的深度协作——例如与CESM参数化工作组（CESM PCWG）开展合作——可确保该研究成果被用于改进全球气候预测模型中的过程参数化方案。团队还将延续达特茅斯学院IGERT项目（Integrative Graduate Education and Research Traineeship, IGERT）中建立的国际合作基础，包括由共同首席研究员波拉申斯基（Polashenski）前往努克（Nuuk）开展为期一周的学术交流之行，期间将在当地高校与卡图阿克文化中心（Katuuaq cultural center）进行讲座。本项目还将涵盖研究生、本科生与高中生的科研培训工作。