Workshops to Establish a Stable North America Reference Frame for EarthScope

为 EarthScope 建立稳定的北美参考系的研讨会

• 批准号: 0545870
• 负责人: Geoffrey Blewitt
• 金额: --
• 依托单位: UNAVCO, Inc.
• 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: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0545870&HistoricalAwards=false
• 关键词: Workshops; Establish; Stable; North; America

0545870BlewittWorkshops to Establish a Stable North America Reference Frame for EarthScopeThe Plate Boundary Observatory (PBO) component of EarthScope will use the science of geodesy to measure the slow deformations in the Earth's crust that are driven by plate tectonics and magmatism. Specifically, the Global Positioning System (GPS) will be used to measure the movements of approximately 1000 points spanning the North America-Pacific plate boundary. These motions must be defined relative to a terrestrial reference frame. Such a frame requires the definition of its Cartesian coordinate axes (including origin, orientation, and scale) and theevolution of these axes in time, as well as precise models of the dynamic Earth. The motions of the Earth's surface due to tectonic processes the region spanning the North America-Pacific plate boundary (the focus of PBO) are most naturally expressed with respect to the stable interiors of either the North America or Pacific plates. A standard reference frame will therefore make it easier to interpret the geodetic data in terms of where the total budget of relative plate motion is being accommodated (for example, how much deformation can be inferred to be offshore?), and how deeply the plate boundary dynamics penetrate into the plate interior (is the Rio Grande Rift in New Mexico still active?). It will also provide a common frame by which to compare results from different analysis groups.The goal of this proposal is to continue research to improve and further develop SNARF, with the eventual goal of handing off operational and regular maintenance to the joint auspices of the USand Canadian national geodetic surveys, as part of their joint remit to maintain the "North American Datum". The research of the SNARF Working Group is based on a volunteer effort and would come at no cost to this grant. In terms of science benefits to EarthScope, the accurate realization of the terrestrial reference frame in terms of scientific models (rather than arbitrary convention) will add significant interpretive value to measured station motions. SNARF will provide a common framework for comparison of geodetic data and geophysical models. Defining a stable frame at the sub-millimeter level requires adequate characterization of Earth deformation processes across the "stable plate interior," a region that by definition is relatively unaffected by plate boundary process. This plate interior provides a stable platform from which to view plate boundary deformation. In terms of broad impacts, the outcome of the SNARF workshops will be a published series of improved reference frames that accurately define the precise coordinates and time evolution of a set of stations representing "stable North America," thus enabling the broad scientific community to realize a common, accurate reference frame for their own research purposes. The SNARF Working Group will provide tools and products for performing model calculations and model-data comparisons in the EarthScope reference frame. The EarthScope initiative will significantly broaden the community using geodetic techniques to study the Pacific-North American plate boundary. Therefore the SNARF working group will not only develop an accurate and stable reference frame,but will also properly describe the use of that reference frame to this larger scientific community. Educational information on using the frame correctly will be made available online. From a national perspective, the SNARF research product will become the US and Canadian national reference frame "NAREF" (North American Reference Frame) to supercede the current definition of the North American Datum (NAD83). This will have profound implications for the US geospatial infrastructure, and all govermental and commercial enterprises who depend on it.

[0545870] blewitt研讨会为地球望远镜建立一个稳定的北美参考框架地球望远镜的板块边界观测站（PBO）部分将使用大地测量学来测量地壳中由板块构造和岩浆活动驱动的缓慢变形。具体来说，全球定位系统（GPS）将用于测量跨越北美-太平洋板块边界的大约1000个点的运动。这些运动必须相对于地面参考系来定义。这样一个框架需要定义它的笛卡尔坐标轴（包括原点、方向和尺度）和这些坐标轴随时间的演变，以及动态地球的精确模型。由于构造过程，横跨北美-太平洋板块边界地区（PBO的焦点）的地球表面运动最自然地表达了北美或太平洋板块的稳定内部。因此，根据相对板块运动的总预算被容纳的位置（例如，有多少变形可以推断为离岸？）以及板块边界动力学渗透到板块内部的深度（新墨西哥州的里约热内卢大裂谷是否仍然活跃？），一个标准的参考框架将更容易解释大地测量数据。它还将提供一个共同的框架来比较来自不同分析小组的结果。该提案的目标是继续研究以改进和进一步发展SNARF，最终目标是将运营和定期维护交给美国和加拿大国家大地测量联合主持，作为他们维护“北美基准”的联合职权范围的一部分。SNARF工作组的研究是基于志愿者的努力，这笔拨款不需要任何费用。就EarthScope的科学效益而言，以科学模型（而不是任意的惯例）精确实现地面参考系将为测站运动增加重要的解释价值。SNARF将为大地测量数据和地球物理模型的比较提供一个通用框架。定义亚毫米级别的稳定框架需要对“稳定板块内部”的地球变形过程进行充分的描述，根据定义，该区域相对不受板块边界过程的影响。这个板块内部提供了一个观察板块边界变形的稳定平台。就广泛的影响而言，SNARF研讨会的成果将是发表一系列改进的参考框架，这些参考框架准确地定义了代表“稳定的北美”的一组台站的精确坐标和时间演变，从而使广泛的科学界能够为自己的研究目的实现一个共同的、准确的参考框架。SNARF工作组将提供工具和产品，用于在EarthScope参考框架中执行模型计算和模型数据比较。EarthScope计划将极大地扩大使用大地测量技术来研究太平洋-北美板块边界的社区。因此，SNARF工作组不仅将开发一个准确和稳定的参考框架，而且还将向这个更大的科学界适当地描述该参考框架的使用。关于正确使用框架的教育信息将在网上提供。从国家的角度来看，SNARF研究产品将成为美国和加拿大的国家参考框架“NAREF”（北美参考框架），以取代目前北美基准（NAD83）的定义。这将对美国的地理空间基础设施以及所有依赖于它的政府和商业企业产生深远的影响。