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.本数据集涵盖位于纽约与新泽西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（backscatter intensity）数据。该数据于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日的三次科考航次中，通过多波束海底测绘系统（multibeam sea floor mapping system）采集获取。本次航次使用安装于加拿大水文局“弗雷德里克·G·克里德”号（Frederick G. Creed）科考船上的Simrad EM 1000多波束回声测深仪（multibeam echo sounder）完成数据采集。该多波束系统配备60个电子定向接收波束，波束间距为2.5度，可覆盖相当于水深7.5倍的海底条带（本次科考区域内条带宽度为100至200米）。海底波束的水平分辨率（horizontal resolution）约为水深的10%（科考区域内为3至5米）；垂直分辨率（vertical resolution）约为水深的1%，即0.3米。基于多波束观测数据生成的地图以3米/像素的空间分辨率（spatial resolution）呈现海底地形、阴影晕渲（shaded relief）以及后向散射强度——该指标用于表征海底质地与粗糙度。