Sea floor topography and backscatter intensity of the historic area remediation site

This data set includes topography and backscatter intensity of the sea floor of the Historic Area Remediation Site (HARS), located offshore of New York and New Jersey. The data were collected with a multibeam sea floor mapping system on surveys conducted November 23 - December 3, 1996, October 26 - November 11, 1998, and April 6 - 30, 2000. The surveys were conducted using a Simrad EM 1000 multibeam echo sounder mounted aboard the Canadian Hydrographic Service vessel Frederick G. Creed. This multibeam system utilizes 60 electronically aimed receive beams spaced at intervals of 2.5 degrees that insonify a strip of sea floor up to 7.5 times the water depth (swath width of 100 to 200 m within the survey area). The horizontal resolution of the beam on the sea floor is approximately 10% of the water depth (3-5 meters in the survey region). Vertical resolution is approximately 1 percent of the water depth, or 0.3 m. Maps derived from the mulitbeam observations show sea floor topography, shaded relief, and backscatter intensity (a measure of sea floor texture and roughness) at a spatial resolution of 3 m/pixel. These data have been reprocessed from those presented in Butman and others (2002) (see cross reference) to correct for an error in the software that projected the data on a sphere rather than on the WGS84 ellipsoid, and to stretch the backscatter intensity and shaded relief images to match the Hudson Shelf Valley images. The horizontal error in placement of the data published by Butman and others (2002) was 0 in the northwestern corner of the HARS, and reached about 12 m in the southeastern corner. Further work is needed to match the backscatter intensity for the 1996, 1998, and 2000 surveys.

本数据集包含位于纽约州与新泽西州近海的历史区域修复场址（Historic Area Remediation Site，HARS）的海底地形与后向散射强度数据。该数据采集于三次勘测任务：1996年11月23日至12月3日、1998年10月26日至11月11日，以及2000年4月6日至30日，均采用多波束海底测绘系统完成。本次勘测搭载于加拿大水文局“弗雷德里克·G·克里德”号（Frederick G. Creed）科考船，使用Simrad EM 1000型多波束测深仪开展作业。该多波束系统配备60个电子定向接收波束，波束间隔为2.5度，可覆盖最大达7.5倍水深的海底条带，勘测区域内条带宽度为100至200米。海底波束的水平分辨率约为水深的10%，在本次勘测区域内为3至5米；垂直分辨率约为水深的1%，即0.3米。由多波束观测数据生成的地图以3米/像素的空间分辨率呈现海底地形、晕渲地貌以及后向散射强度（用于表征海底质地与粗糙度）。上述数据是对Butman等人（2002）发布的原始成果进行重新处理后的版本：修正了原投影软件将数据映射至球面而非WGS84椭球体的误差，并对后向散射强度与晕渲地貌图像进行对比度拉伸，以匹配哈德逊陆架谷（Hudson Shelf Valley）的图像标准。Butman等人（2002）发布的数据在HARS西北角的水平定位误差为0，在东南角的最大定位误差约为12米。目前仍需开展进一步工作，以统一1996、1998及2000年三次勘测的后向散射强度数据。