Collaborative research: Spatial and temporal variability of surface albedo and light absorbing chemical species in 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格陵兰内陆穿越计划（Greenland Inland Traverse, GrIT），该路线往返于图勒与格陵兰冰盖最高点（Summit, Greenland）之间，可覆盖格陵兰冰盖（Greenland Ice Sheet, GIS）内空间分布多样的区域，以深入解析反照率（albedo）的变化特征及影响反照率的积雪特性。GrIT路线为研究格陵兰全域多样的积雪带提供了独特契机：涵盖消融区、融雪浸透区、渗滤区与干雪区，这些区域的反照率取值范围跨度较大，同时积雪物理特性与吸光性化合物（尘埃、元素碳、棕碳）的浓度均存在显著差异。本项目的野外考察工作将在2013年与2014年春季两个季度开展。研究手段包括在穿越路线沿线停靠点开展同步的每日观测：积雪光谱反照率、积雪物理特性（比表面积、密度）、地表积雪光吸收特性（水溶性化合物与颗粒物的波长依赖性吸收），以及痕量元素、有机碳与元素碳的浓度。此外，在日照月份期间，团队将依托沿穿越路线部署的自动监测站，持续监测光谱反照率的时间演变过程，以追踪积雪反照率的季节变化，并明确这些变化与积雪物理化学组成的关联机制。本项目的研究成果将形成一套独特的数据集，全面刻画格陵兰地表反照率的时空变化特征，以及积雪的物理与化学特性，该数据集对建模研究、冰量平衡评估与遥感领域均具有广泛的应用价值。项目团队将通过会议报告、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（例如与社区地球系统模型极地气候工作组（CESM PCWG）开展合作），确保该研究成果可用于优化预测性全球气候模型中的过程参数化方案。团队还将延续在达特茅斯学院IGERT项目中开启的国际合作，包括共同首席研究员（co-Principal Investigator, co-PI）波拉申斯基（Polashenski）将赴努克开展为期一周的交流活动，期间将在当地高校与卡图阿克文化中心发表演讲。本项目还将涵盖研究生、本科生与高中生的科研培训工作。