Collaborative Research: A New Radiostratigraphic Database for the Greenland Ice Sheet and Critical Boundary Conditions for the Next Generation of Ice-Sheet Models

合作研究：格陵兰冰盖的新放射地层数据库和下一代冰盖模型的关键边界条件

• 批准号: 1243584
• 负责人: Mark Fahnestock
• 金额: $ 11.29万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1243584&HistoricalAwards=false
• 关键词: Collaborative; Research; New; Radiostratigraphic; Database

Predictive ice-sheet models are our best tools for understanding the cumulative effects of forcings and feedbacks upon the Greenland Ice Sheet (GIS). However, these models lack detail concerning the GIS basal boundary condition, which is a critical control upon ice flow. They also do not take advantage of the wealth of information contained in its internal radiostratigraphy, but that could become a key component of their validation and application as predictive tools.To address this need for new constraints on ice-sheet models, funds are provided to develop, validate, and analyze a new radiostratigraphic database of the GIS. The database will be derived from past (e.g., PARCA, CReSIS) and ongoing (e.g., IceBridge) airborne radar-sounding campaigns. The research objectives are three-fold:1. Development of novel automated layer-picking techniques. Picking widespread layers in radar data is often a time-intensive process. Recent advances permit dramatic improvements in automated layer picking, which will yield both insights into the nature of ice-sheet radiostratigraphy and accelerate a more precise study of ice-flow history from it.2. Holocene surface and basal mass balance of the GIS. The picked radiostratigraphy will be combined with strain-rate modeling to map both Holocene surface-accumulation and basal melt rates across the GIS. This proven method will be extended beyond its previous application to northern Greenland, with uncertainties quantified using their knowledge of past ice-flow conditions. This study will both inform understanding of Greenland?s subglacial geology and provide key boundary conditions for ice-flow models of the GIS.3. LAYERMAP: A dated radiostratigraphic model of the GIS. The radiostratigraphic database will be gridded in a manner similar to that for bed elevation underneath ice sheets. LAYERMAP will contribute to the advancement of IPCC-level ice-sheet models of the GIS, whose projections of its future evolution will hinge on data validation of its modern state. In addition, LAYERMAP will provide a means of mapping basal conditions and englacial drainage features across the GIS.Observations suggest a recent acceleration of the contribution of a degrading Greenland Ice Sheet to global sea level rise. Present projections of the rate of sea level rise are bounded by broad error bars, preventing accurate assessment of the response necessary to mitigate the impact of sea level rise. This project will develop data sets needed to validate and constrain models of the Greenland Ice Sheets contribution to future sea level.

预测冰盖模型是我们了解格陵兰冰盖（GIS）上的强迫和反馈的累积效应的最佳工具。然而，这些模型缺乏有关GIS的基础边界条件，这是一个关键的控制冰流的细节。他们也没有利用其内部放射性地层学中所包含的丰富信息，但这可能成为其验证和应用的关键组成部分作为预测tools.To解决这一需要新的约束冰盖模型，资金提供开发，验证和分析一个新的放射性地层数据库的GIS。数据库将从过去的（例如，PARCA、CReSIS）和正在进行的（例如，冰桥）机载雷达探测战役。研究目标有三个方面：1。开发新型自动化层拾取技术。在雷达数据中挑选广泛的层通常是一个时间密集的过程。最近的进展允许自动化层拾取的显着改进，这将产生对冰盖放射性地层学性质的见解，并加速从中更精确地研究冰流历史。GIS的全新世地表和基底物质平衡。挑选的放射性地层学将结合应变率建模，以映射整个GIS的全新世地表堆积和基底融化速率。这种经过验证的方法将超越之前在格陵兰岛北方的应用，并利用他们对过去冰流条件的了解来量化不确定性。这项研究将有助于了解格陵兰岛？的冰下地质，并提供关键的边界条件的地理信息系统的冰流模型。LAYERMAP：GIS的一种定年放射性地层模型。放射性地层学数据库将以类似于冰盖下海床高程的方式进行网格化。LAYERMAP将有助于推进IPCC一级的地理信息系统冰盖模型，其未来演变的预测将取决于其现代状态的数据验证。此外，LAYERMAP还将提供一种手段，绘制整个地理信息系统的基础条件和冰内排水特征，观测表明，最近格陵兰冰盖的退化加速了全球海平面的上升。 目前对海平面上升速度的预测都有很宽的误差线，无法准确评估减轻海平面上升影响所需的应对措施。 该项目将开发验证和限制格陵兰冰盖对未来海平面影响的模型所需的数据集。