Surficial Sediment Data Collected During U.S. Geological Survey (USGS) RV Rafael cruise 2011-006-FA in Block Island Sound off Southwestern Rhode Island (2011_006BISSEDDATA.SHP, Geographic, WGS84)

The USGS, in cooperation with NOAA, is producing detailed maps of the seafloor off southern New England. The current phase of this cooperative research program is directed toward analyzing how bathymetric relief relates to the distribution of sedimentary environments and benthic communities. As part of this program, digital terrain models (DTMs) from bathymetry collected as part of NOAA's hydrographic charting activities are converted into ESRI raster grids and imagery, verified with bottom sampling and photography, and used to produce interpretations of seabed geology and hydrodynamic processes. Although each of the 7 continuous-coverage, completed surveys individually provides important benthic environmental information, many applications require a geographically broader perspective. For example, the usefulness of individual surveys is limited for the planning and construction of cross-Sound infrastructure, such as cables and pipelines, or for the testing of regional circulation models. To address this need, we integrated the 7 contiguous multibeam bathymetric DTMs into one dataset that covers much of Block Island Sound. The new dataset is adjusted to mean lower low water, is provided in UTM Zone 19 NAD83 and geographic WGS84 projections, and is gridded to 4-m resolution. This resolution is adequate for seafloor-feature and process interpretation, but small enough to be queried and manipulated with standard GIS programs and to allow for future growth. Natural features visible in the grid include boulder lag deposits of submerged moraines, sand-wave fields, and scour depressions that reflect the strength of the oscillating tidal currents. Bedform asymmetry allows interpretations of net sediment transport. Together the merged data reveal a larger, more continuous perspective of bathymetric topography than previously available, providing a fundamental framework for research and resource management activities off this portion of the Rhode Island coast. Interpretations were derived from the multibeam echo-sounder data and the ground-truth data used to verify them.
For more information on the ground-truth surveys see http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2011-006-FA

美国地质调查局（USGS）与美国国家海洋和大气管理局（NOAA）合作，正在编制新英格兰南部海域的详细海底地图。当前这项合作研究计划的核心目标，是分析水深地形起伏与沉积环境分布以及底栖生物群落之间的关联机制。作为该计划的一部分，研究人员将NOAA水文海图测绘活动中采集的水深数据生成的数字地形模型（DTMs），转换为ESRI栅格网格与影像数据，结合底质采样与摄影资料开展验证工作，并据此完成海底地质与水动力过程的解译。

尽管7项连续覆盖且已完成的勘测各自均可提供重要的底栖环境信息，但诸多应用场景需要更具广度的地理视角。例如，单份勘测数据在跨海湾基础设施（如电缆与管道）的规划建设，或是区域环流模型的验证等工作中，其适用性存在明显局限。为满足这一需求，研究团队将7块连续的多波束水深数字地形模型整合为单一数据集，覆盖了布洛克岛湾的大部分海域。

该新数据集已校正至平均低潮水位，提供UTM 19区NAD83与地理坐标系WGS84两种投影格式，网格分辨率为4米。这一分辨率既能满足海底地貌与过程解译的专业需求，又足够精细，可通过标准地理信息系统（GIS）程序进行查询与处理，同时预留了未来扩展的空间。网格中可见的自然地貌包括淹没冰碛的砾石滞后沉积、沙波群，以及反映振荡潮流强度的冲刷洼地。底形不对称性可用于推断沉积物的净输运方向。

整合后的数据集相较于此前的单一成果，展现了更广阔且连续的水深地形全貌，为罗德岛海岸这片海域的科研与资源管理活动提供了核心基础框架。相关解译结果源自多波束测深仪数据与用于验证的实地勘测数据。

如需了解实地验证勘测的更多信息，请访问：http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2011-006-FA