Collaborative Research: A field validated model for melt water infiltration and runoff from the Greenland Icesheet

合作研究：格陵兰冰盖融水渗透和径流的现场验证模型

• 批准号: 0612374
• 负责人: Neil Humphrey
• 金额: $ 15.57万
• 依托单位: University of Wyoming
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0612374&HistoricalAwards=false
• 关键词: Collaborative; Research; field; validated; model

ABSTRACTHarperOPP-0612506PffefferOPP-0612351HumphreyOPP-0612374Satellite observations suggest substantial year-to-year increases in surface melt extent of the Greenland Ice Sheet (GIS). Both the area and duration of snow melting in the percolation facies, a wide band of intermediate elevation that circumscribes the ice sheet, are increasing. The fate of the melt water, however, is unclear as in-situ observations in Greenland's percolation facies have been extremely limited. The ultimate hydrologic result of these changes is a significant change in meltwater production and runoff from GIS, however, the coupling between snow processes and runoff are poorly documented. In particular, the runoff limit, the altitude above which seasonal melt infiltrates, refreezes, and does not escape, lies within the higher part of the percolation facies, but its precise location is generally unknown, and the response of the runoff limit to warming is poorly understood. Current models for present and future contributions of GIS to sea level rise use a model which established rough bounds on the response of the "runoff limit" to secular increases in melt. This research will quantify melt water runoff processes and changes in near-surface firn densification in the percolation facies of GIS and will produce a new and highly improved model for runoff that is anchored in experimental observations. Experiments will be conducted at sites along a transect in the region of Crawford Point, extending from about 2025 m to 1500 m elevation. Specific objectives are twofold: 1) the Principal Investigators will determine km-scale melt water flow velocities and pathways which will serve as calibration for their runoff model; and 2). they will investigate change in near-surface densification rates and processes in records that span over 25 years. This work will increase our understanding and prediction capabilities of the fraction of meltwater which runs off the ice sheet, document change in important physical processes occurring on the ice sheet, and provide rare ground observations for comparison to satellite based measurements of surface melt. Each of these has important implications for interpretation of the ice sheet's surface elevation, mass balance, and flow dynamics and ultimately, global eustatic sea level.Broader Impacts: The Principal Investigators are active teaching faculty engaged in undergraduate and graduate teaching, and graduate student mentoring. They will collectively teach over 90 credit hours of undergraduate and graduate courses. This research and related scientific issues will add pedagogical benefit to numerous courses. This project will lead to at least four graduate degrees. They regularly conduct outreach activities with k-12, the general public, and the oil and gas industry.

Apptractharperopp-0612506Pffefferpp-0612351HumphreyOpp-0612374Satellite观测表明，格陵兰冰盖（GIS）的表面熔体范围（GIS）的表面熔体范围逐年逐年增加。渗滤相的雪融化的面积和持续时间都在增加冰盖的范围内的宽带。 然而，熔体水的命运尚不清楚，因为格陵兰渗透相的原位观察结果极为有限。这些变化的最终水文结果是GIS的融合产量和径流发生了重大变化，但是，雪过程和径流之间的耦合记录很少。特别是，径流极限，高于季节性熔体浸润，重新冻结和不逃脱的高度，位于渗透相的较高部分之内，但其确切的位置通常是未知的，并且对变暖的径流限制的响应也很熟悉。 GIS对海平面上升的当前和未来贡献的当前模型使用了一个模型，该模型建立了“径流极限”对世俗增长熔体的响应的粗略界限。这项研究将量化熔体径流过程，并在GIS的渗透相中近地表FIRN致密化的变化，并将产生一种新的且高度改进的径流模型，以固定在实验观测中。实验将在克劳福德角（Crawford Point）区域的横断面进行，从约2025 m延伸到1500 m的海拔。具体目标是双重的：1）主要研究人员将确定KM规模的熔体水流速度和途径，这将作为其径流模型的校准；和2）。他们将调查25年以上记录中近地表致密化率和过程的变化。这项工作将提高我们对冰盖融化的融合水分部分的理解和预测能力，文档在冰盖上发生的重要物理过程的变化，并提供了罕见的地面观测值，以与基于卫星的表面熔体测量结果进行比较。这些中的每一个都对解释冰盖的表面高度，质量平衡和流动动态以及最终的全球欣赏海平面的解释具有重要意义。BROADER的影响：主要研究人员是积极从事大学教学教师的积极教学教师，从事本科和研究生教学以及研究生教学。他们将集体教授90多个学分的本科和研究生课程。这项研究和相关的科学问题将为众多课程增加教学益处。该项目将至少导致四个研究生学位。他们定期与K-12，公众以及石油和天然气行业进行外展活动。