RV Tangaroa Voyage TAN2021_V01 EM2040 Multibeam Echosounder Data

This record describes shallow 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 EM2040 was used to obtain swath bathymetry, backscatter, and water column data in shallower water (20 - 300 m), using Kongsberg Seafloor Information System (SIS) version 4.3.2 acquisition system. The EM2040 is a single RX system, with 256 beams (or 576 beams in dual swath mode), yielding 400 soundings (or 800 soundings in High Density 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 129 files totalling 11.6 GB of raw data in this dataset. There are 129 files totalling 152 GB of water column 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) 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.

本数据集记录了坦加罗阿号（RV Tangaroa）科考船航次TAN2021_V01（NIWA TAN2113）所采集的浅层多波束数据（shallow multibeam data）。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（Commonwealth Scientific and Industrial Research Organisation, CSIRO）海洋国家设施（Marine National Facility, MNF）执行科考任务。本次航次包含两项核心目标：一是回收此前在IN2020_v06航次中部署于麦夸里岛（Macquarie Island）周边的27台海底地震仪（Ocean Bottom Seismometers）；二是完成麦夸里海岭（Macquarie Ridge）沿线的多波束与浅地层剖面测绘，并在航行转场期间采集新增多波束数据。
本次航次采用Kongsberg Maritime EM2040多波束回声测深系统（multibeam echosounder），搭配Kongsberg海底信息系统（Seafloor Information System, SIS）4.3.2版本采集软件，在20~300米的浅水区获取条带测深（swath bathymetry）、反向散射（backscatter）与水柱数据（water column data）。EM2040为单接收阵系统（single RX system），单条带模式下支持256个波束（双条带模式下可达576个波束），单次可输出400个测深点（高密度模式（High Density mode）下可提升至800个测深点）。与多波束回声测深数据同步采集的水柱数据，可记录每个波束对应整个水柱的接收振幅信息。
本数据集的测深数据（bathymetry data）与反向散射数据以*.all原始格式存储，水柱反向散射数据以*.wcd格式存储于CSIRO。本次数据集共包含129个原始数据文件，总容量达11.6 GB；另有129个水柱数据文件，总容量为152 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姿态与位置校正。
原始数据（*.all文件）分别通过QPS Qimera v2.4.2处理测深数据，通过QPS Geocoder Toolbox（FMGT）v7.10.0处理声学海底反向散射数据。
编辑完成后，Qimera将为每个*.all文件生成对应的*.gpd格式文件。研究人员对测深数据质量开展核查，为每个调查区域生成不同分辨率的地形曲面，并通过二维与三维手动方式完成数据清洗，必要时采用中等样条滤波器进行平滑处理。网格化测深曲面采用WGS84 / UTM 57S（EPSG:32757）坐标系进行投影，分辨率可按需调整。最终整合所有测深数据集，并使用ArcGIS Pro v2.8.3生成相关专题地图。
水柱数据（*.wcd格式）未在航次船上进行预处理。
本数据集的补充说明详见"NIWA Voyage Report 2022007WN.pdf"，该报告可应要求向CSIRO地球物理勘测与制图（Geophysical Survey and Mapping, GSM）小组申请获取。