High-Resolution Gravity, Tomography, and Seafloor Roughness

知识价值：在过去的5年中，改进的全球海洋重力和测深网格以1分钟分辨率被构建。重新跟踪了1年的ERS-1和1.5年的Geosat卫星高度计原始波形，这使得全球海洋重力场的精度提高了40%，从而可以对转换断层、海山、海底结构和海洋混合进行新的科学研究。改进的重力与新的全球深度测深组合相结合，形成了一个新的1分钟分辨率的全球测深网格。目前的项目涉及将1分钟分辨率的海洋重力模型与即将发布的全球重力模型（EGM08）合并，该模型完成了球谐度2160（5分钟分辨率），从而形成横跨海岸线的无缝重力场。基于高度计数据密度、高度计噪声以及与船上重力的比较，将构建一个海洋重力的不确定性网格。将生成一个匹配的测深/地形网格，重点是浅海（1000米）区域，在那里新的测深数据正在迅速可用。将开发一个1分钟数据源网格，提供与原始探测数据的联系。将为所有这些数据产品提供网络访问，包括：网格、清洁的声音和图像/地图。这些新的数据资源将用于研究扩展速率对脊分割、岩石圈强度和地壳结构的影响。这些对全球海洋重力和测深网格的改进将有利于大陆边缘的科学和石油勘探研究。这些数据是美国国家科学基金会支持的许多科学研究的基础，并有利于广泛的海洋科学调查。这个项目将确保所有人都能免费获得这些数据。更广泛的影响：全球水深图用于科学界以外的许多领域，包括：K-12地球科学和海底地理教学；地球科学与板块构造；海洋法；矿产勘查;光纤电缆布线规划及公众普遍关心的问题。这些信息可以在我们的网站http://topex.ucsd.edu上以各种格式提供给专家、中级和新手用户。

Intellectual Merit: Over the past 5 years an improved global marine gravity and bathymetry grids has been constructed with 1-minute resolution. Raw satellite altimeter waveforms from 1 year of ERS-1 and 1.5 years of Geosat were re-tracked, which has resulted in a 40% improvement in the accuracy of the global marine gravity field, enabling new scientific investigations of transform faults, seamounts, seafloor fabric, and ocean mixing. The improved gravity, combined with a new assembly of global depth soundings, is resulting in a new global bathymetry grid at 1 minute resolution. The present project involves merging the 1-minute resolution marine gravity model with a soon-to-be-published global gravity model (EGM08) complete to spherical harmonic degree 2160 (5 minute resolution), resultig in a seamless gravity field across the shorelines. A grid of uncertainty in the marine gravity will be constructed, based on altimeter data density, altimeter noise, and comparisons with shipboard gravity. A matching bathymetry/topography grid will be generated, with a focus on shallow ocean (1000 m) areas where new soundings are rapidly becoming available. A 1-minute data source grid will be developed that provides the link to the original sounding data. Web access will be provided to all of these data products including: grids, cleaned soundings, and images/maps. These new data resources will be used to investigate the effects of spreading rate on ridge segmentation, lithospheric strength, and crustal structure. These improvements to the global marine gravity and bathymetry grids will benefit scientific and petroleum exploration studies of continental margins. These data are foundational to many scientific studies supported by NSF and benefit a wide range of ocean science investigations. This project will ensure the data are freely available to everyone.Broader Impacts: Global bathymetric charts are used in many areas outside of the scientific community including: K-12 teaching of earth science and seafloor geography; undergraduate-level earth science and plate tectonics; law of the sea; mineral exploration; planning of fiber-optic cable routing and general interest by the public. This information is available on our web site http://topex.ucsd.edu in a variety of formats for expert, intermediate, and novice users.