ArcticDEM Production

该项目将利用Blue Waters持续的千万亿次计算能力，构建第一个高分辨率（2m）、高质量（5m不确定性）和公开分布的数字高程模型（DEM）集，涵盖北纬60度以上的所有北极陆地，包括格陵兰岛、阿拉斯加和堪察加半岛。需要这样一套DEM来测量和了解气候变化和人类利用对北极景观造成的快速、持续的变化，以及北极社区的缓解和适应规划。获取和维护图像的资源、后期处理结果的工具、软件开发时间和分布DEM的方法都得到了保障。Blue Waters上使用的计算时间需要提供整个北极的DEM覆盖。民主党将免费提供给科学界和广大公众，并将履行美国作为北极理事会主席任期的一部分对其北极伙伴的承诺。一个全面的、精细的北极DEM的产生将改变北极研究界和北极社会。dem将提供带时间戳的冰范围和冰面高度观测，并可以在不断变化的环境强迫的背景下进行检查。dem的细节将允许对冰川上水文的演变进行检查，直至单个湖泊和溪流的水平。正如最近发表在《自然》杂志上的，由冰下水文变化引起的地表沉降也将用于研究（I. M. Howat et al. 2015; Palmer, McMillan, and Morlighem 2015; Willis et al. 2015）。此外，北极DEM的范围几乎与北半球永久冻土的范围完全匹配，因此DEM集将有可能检查主要的热岩溶变化和冰缘山坡演变。对永久冻土区的静态、动态、宏观和微观表面地形进行检查是美国国家科学院的一项主要建议，以进一步了解永久冻土区及其捕获的碳是如何应对气候变暖的（国家研究委员会2014年）。此外，dem将能够详细检查海岸演变，突出显示海岸线以恒定速率侵蚀以及对海岸线冰推或ivu等极端事件的反应。在数据集中，湖泊大小和位置（可能还有深度）以及河流和三角洲形态的变化分布将会很明显，对湿地、生态系统、野生动物管理和可持续性产生影响。冰/火山相互作用、过程地貌学、构造地貌学、板块边界相互作用、断层表达、断层演化、冰川地貌学和弯曲湖岸线衍生的固体地球动力学都将从新的数据中得到提供。此外，大气科学的研究，如小气候、山谷尺度大气动力学和东风的研究，将使用新的精细尺度地形来进行缩小尺度或微区域大气模型。社区也可能使用dem来预测和解决永久冻土的影响、海平面上升、洪泛区划分和灾害管理。

The project will use the sustained, petascale computing capabilities of Blue Waters to construct the first high-resolution (2m), high-quality (5m uncertainty), and openly distributed digital elevation model (DEM) set of all Arctic land masses above 60 degree N, including all of Greenland, Alaska, and Kamchatka. Such a DEM set is needed for measuring and understanding rapid, ongoing changes to the Arctic landscape resulting from climate change and human use, as well as mitigation and adaptation planning for Arctic communities. Resources for obtaining and maintaining the imagery, tools for post-processing the results, software development time, and methods for distributing the DEM have been secured. The compute time used on Blue Waters is needed to provide DEM coverage of the entire Arctic. DEMs will be provided at no cost to the science community and public at large, and will fulfill the United States' commitment to its Arctic partners as part of its tenure as chair of the Arctic Council. The production of a comprehensive, fine-scale Arctic DEM will transform the Arctic research community and Arctic society. The DEMs will provide time-stamped observations of ice extent and ice surface height and can be examined within the context of changing environmental forcings. The detail of the DEMs will allow the evolution of supraglacial hydrology to be examined down to the level of individual lakes and streams. As published recently in Nature, surface subsidence caused by subglacial hydrological changes will also be available for study (I. M. Howat et al. 2015; Palmer, McMillan, and Morlighem 2015; Willis et al. 2015). Furthermore, the extent of Arctic DEM almost exactly matches the extent of permafrost in the northern hemisphere, so the DEM set will make it possible to examine major thermokarst changes and periglacial hill slope evolution. Examination of the static, dynamic, macro- and micro-surface topography of permafrost regions is a major recommendation of the U.S. National Academy of Sciences to enablefurther understanding of how permafrost regions and their trapped carbon are responding to a warming climate (National Research Council 2014). Additionally, the DEMs will enable detailed examination of coastal evolution, highlighting shoreline erosion at constant rates and in response to extreme events such as a shoreline ice-shove, or ivu. Changing distribution of lake size and location (and possibly depth) and river and delta morphology will be apparent in the data set, with ramifications for wetlands, ecosystems, and wildlife management and sustainability. Ice/volcano interactions, process geomorphology, tectonic geomorphology, plate boundary interactions, fault expressions, fault evolution, glacial geomorphology, and solid earth geodynamics derived from bending lake shorelines will all be provided from the new data. Moreover, atmospheric science pursuits such as the study of microclimates, valley-scale atmospheric dynamics and foehn winds will use the new fine-scale topographies for downscaled or micro-region atmospheric models. Communities are also likely to use the DEMs to anticipate and address permafrost impacts, rising sea level, floodplain delimitation and disaster management.