RV Tangaroa Voyage TAN2021_V01 EM302 Multibeam Echosounder Data

This record describes deeper multibeam data collected on RV Tangaroa voyage TAN2021_V01 (NIWA TAN2113), which was carried out on a contract to the CSIRO MNF from 9th November to 4th December 2021. The voyage had two objectives, which were to recover 27 Ocean Bottom Seismometers which had been deployed around Macquarie Island on IN2020_v06, and complete multibeam and sub bottom profiler mapping along the crest of the Macquarie Ridge and collect new multibeam data during transits.The Kongsberg Maritime EM302 was used to obtain swath bathymetry, backscatter, and water column data in deeper water (down to 7000 m), using Kongsberg Seafloor Information System (SIS) version 4.3.2 acquisition system. The EM302 is a 1 TX by 2 RX system, with 288 beams (or 576 beams in dual swath mode), yielding 432 soundings (or 864 soundings in Dual Swath mode ). Water column data, which show the received amplitude of the entire water column for each beam, were recorded simultaneoulsy with the multibeam echosounder data. Data are stored in *.all raw format for bathymetry and backscatter and *.wcd format for watercolumn backscatter at CSIRO. There are 201 files totalling 25.2 GB of raw data in this dataset. There are 200 files totalling 43.8 GB of water colomn data.Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position.Raw data (*.all files) were processed using QPS Qimera v2.4.2 for bathymetry and QPS Geocoder Toolbox (FMGT) v7.10.0 for acoustic seafloor backscatter. *.gpd files were generated by Qimera for each *.all file after editing. The quality of the bathymetry data was examined, and surfaces of varying resolution generated for each survey area. The data were cleaned in both 2D and 3D manually. Where appropriate a medium spline filter was used. Gridded bathymetric surfaces were projected in WGS84 / UTM zone 57S (EPSG:32757) coordinate reference system at varying resolutions. Bathymetry datasets were collated, and maps produced in ArcGIS Pro v2.8.3.Water column data files (.wcd) consisting of 165 files, 31.1 GB, were not processed onboard.Additional information regarding this dataset is contained in the "NIWA Voyage Report 2022007WN.pdf". The report is available from Geophysical Survey and Mapping (GSM) group at CSIRO upon request.

本记录记述了“坦加罗阿号”研究科考船（RV Tangaroa）航次TAN2021_V01（NIWA TAN2113）所采集的深水多波束数据，该航次于2021年11月9日至12月4日受委托为澳大利亚联邦科学与工业研究组织（CSIRO）海洋国家设施（Marine National Facility, MNF）执行任务。本次航次包含两项核心目标：一是回收2020年航次IN2020_v06在麦夸里岛周边部署的27台海底地震仪（Ocean Bottom Seismometer, OBS）；二是完成麦夸里海岭沿线的多波束与浅地层剖面仪（sub bottom profiler）测绘，并在航行途中采集新的多波束数据。本次作业采用康斯伯格海事公司（Kongsberg Maritime）EM302多波束系统，搭载康斯伯格海底信息系统（Seafloor Information System, SIS）4.3.2版本采集系统，可在水深达7000米的区域获取条带测深（swath bathymetry）、声学反向散射（backscatter）与水柱数据（water column data）。EM302系统采用1发射端（Transmit, TX）×2接收端（Receive, RX）的配置，拥有288个波束（双条带模式下为576个波束），单次可获取432个测深点（双条带模式下为864个测深点）。水柱数据可记录每个波束对应的全水柱接收振幅，与多波束回声测深仪（multibeam echosounder）数据同步采集。本数据集的测深与反向散射原始数据采用*.all格式存储，水柱反向散射数据采用*.wcd格式存储，均存放于澳大利亚联邦科学与工业研究组织（CSIRO）。其中，原始数据包含201个文件，总容量达25.2 GB；水柱数据包含200个文件，总容量为43.8 GB。数据采集阶段已应用声速剖面（sound velocity profiles）对数据进行校正；*.all格式存储的测深数据已完成运动与位置校正。原始*.all格式数据分别通过QPS Qimera v2.4.2与QPS地理编码工具箱（Geocoder Toolbox, FMGT）v7.10.0完成测深与声学海底反向散射数据的处理。经编辑后，Qimera会为每个*.all文件生成对应的*.gpd格式文件。研究人员对测深数据质量进行了核查，并为每个测区生成了不同分辨率的地形表面模型；数据已通过二维与三维人工方式完成清理，必要时采用了中等样条滤波器进行平滑处理。网格化测深地形表面均采用WGS84 / UTM 57S（EPSG:32757）坐标系进行投影，分辨率可灵活调整。测深数据集已完成整合，并通过ArcGIS Pro v2.8.3生成相关测绘图件。包含165个文件、总容量31.1 GB的.wcd格式水柱数据未在船上进行处理。本数据集的补充信息详见《NIWA航次报告2022007WN.pdf》，有需求者可向澳大利亚联邦科学与工业研究组织（CSIRO）地球物理调查与测绘组（Geophysical Survey and Mapping, GSM）申请获取该报告。