U.S. Geological Survey calculated half interpercentile range (half of the difference between the 16th and 84th percentiles) of wave-current bottom shear stress in the South Atlantic Bight from May 2010 to May 2011 (SAB_hIPR.shp, polygon shapefile, Geographic, WGS84)

The U.S. Geological Survey has been characterizing the regional variation in shear stress on the sea floor and sediment mobility through statistical descriptors. The purpose of this project is to identify patterns in stress in order to inform habitat delineation or decisions for anthropogenic use of the continental shelf. The statistical characterization spans the continental shelf from the coast to approximately 120 m water depth, at approximately 5 km resolution. Time-series of wave and circulation are created using numerical models, and near-bottom output of steady and oscillatory velocities and an estimate of bottom roughness are used to calculate a time-series of bottom shear stress at 1-hour intervals. Statistical descriptions such as the median and 95th percentile, which are the output included with this database, are then calculated to create a two-dimensional picture of the regional patterns in shear stress. In addition, time-series of stress are compared to critical stress values at select points calculated from observed surface sediment texture data to determine estimates of sea floor mobility.美国地质调查局（U.S. Geological Survey）通过统计描述符对海底剪切应力与沉积物运移性的区域差异开展表征工作。本项目旨在识别剪切应力的分布模式，以此为大陆架生境划分或人类开发利用决策提供参考依据。本次统计表征覆盖了从沿岸至约120米水深的大陆架区域，空间分辨率约为5千米。研究团队通过数值模型生成波浪与环流的时间序列数据，并利用稳态与振荡流速的近底输出结果以及底床粗糙度估算值，以1小时间隔计算海底剪切应力的时间序列。随后计算中位数、95分位数等统计描述指标（该数据库包含此类输出结果），以此构建海底剪切应力区域分布模式的二维可视化图景。此外，研究人员将应力时间序列与通过实测表层沉积物粒度数据计算得到的选定点位临界应力值进行对比，以此估算海底沉积物运移性。