Multibeam and ROV Data from the Western Rio Grande Rise

- The two subbottom profiles were acquired aboard the N/Oc Alpha Crucis in February of 2018 with a Knudsen CHIRP 3260 operating at 3.5 kHz frequency and 2 kW power. Data was then converted to SEGY, and a simple burst noise filter was applied. Navigation was provided by an Applanix OceanMaster Inertial Navigation System (IMU) connected to two Trimble GPS antennas. - Multibeam bathymetry data was acquired during the three expeditions: (1) For the Alpha Crucis, acquisition occurred using a Reson Seabat 7160 echosounder operating at 44 kHz. Navigation data was provided by an Applanix OceanMaster connected to two Trimble GPS antennas. Survey speed was between 4 – 4.5 knots. Sound Velocity Profiles were collected at least every other day during the survey and at least once per survey to full depth. The Patch Test was carried out in area north of the Cruzeiro do Sul Rift and applied retrospectively to the data already collected. Data processing was performed using Teledyne PDS 2000 software, following a basic workflow of spike removal, gridding, and interpolation of no-data cells. (2) For the NPqHo aboard the Vital de Oliveira, acquisition occurred using the Kongsberg SIS software with a Kongsberg EM122 echosounder operating at 12 kHz frequency and with navigation provided by a SeaPath 330 positioning system with two GNSS antennas without differential positioning. Survey speed was between 4 – 4.5 knots. Data processing occurred during acquisition on the software CARIS HIPS and SIPS and postprocessing on the software EIVA Navimodel. (3) For the operation aboard the RSS Discovery, acquisition occurred with a Kongsberg EM122 multibeam system equipped on the ship hull that used the Kongsberg SIS software and was processed in CARIS HIPS SIPS. Sound velocity data was acquired during two dips and incorporated into the data during processing. All multibeam datasets were merged and interpreted together using the software EIVA Navimodel Producer. All multibeam datasets were merged, interpreted together using the software EIVA Navimodel Producer and exported in ASCII format. - Seafloor imaging was undertaken with the HyBIS from the UK National Oceanography Centre aboard the RSS Discovery in October of 2018. HyBIS is a ROV capable of reaching 6000 m of depth, controlled by a fibre optic cable connected to the ship, and equipped with two Super Scorpio HD cameras and one Sony HDR-CX560V camera (Murton et al., 2012). HyBIS dive objectives were to survey and sample the areas of high interest based on the analysis of the multibeam data. Depth range of the survey occurred from 620 m to 1480 m. Interpretation of ROV data occurred via the visual analysis of all video recordings post-survey, with the objective of identifying and interpreting the main geomorphological and seabed erosional structures recorded in the data.本数据集包含2组浅地层剖面（subbottom profiles），于2018年2月在N/Oc Alpha Crucis号科考船上获取，使用工作频率为3.5 kHz、功率2 kW的Knudsen CHIRP 3260型设备采集。采集所得数据随后被转换为SEGY格式，并施加了简单脉冲噪声滤波器。导航数据由搭载两台天宝（Trimble）GPS天线的Applanix OceanMaster惯性导航系统（Inertial Navigation System，IMU）提供。 多波束测深（multibeam bathymetry）数据由3次科考航次获取： (1) Alpha Crucis航次：使用工作频率44 kHz的Reson Seabat 7160型回声测深仪完成数据采集，导航数据由搭载两台天宝GPS天线的Applanix OceanMaster系统提供。本航次测量航速介于4~4.5节。声速剖面（Sound Velocity Profiles）在测量期间至少每两天采集一次，且每次航次至少完成一次全水深采集。补丁测试（Patch Test）在南克鲁兹裂谷（Cruzeiro do Sul Rift）北侧区域开展，并回溯应用于已采集的全部数据。数据处理采用Teledyne PDS 2000软件完成，遵循去除尖峰、网格化以及无数据单元格插值的基础工作流程。 (2) NPqHo航次：搭载于Vital de Oliveira号船上，使用Kongsberg SIS软件搭配工作频率12 kHz的Kongsberg EM122型回声测深仪完成采集，导航由搭载两台GNSS天线且未启用差分定位的SeaPath 330定位系统提供。本航次测量航速介于4~4.5节。数据处理在采集阶段通过CARIS HIPS and SIPS软件完成，后处理阶段则采用EIVA Navimodel软件进行。 (3) RSS Discovery号科考作业：采用安装于船舷的Kongsberg EM122多波束系统完成采集，配套Kongsberg SIS软件，数据处理在CARIS HIPS SIPS中完成。两次下潜期间采集了声速数据，并在处理过程中整合入数据集。所有多波束数据集均通过EIVA Navimodel Producer软件完成合并与协同解译，并最终以ASCII格式导出。所有多波束数据集均通过EIVA Navimodel Producer软件完成合并与协同解译，并以ASCII格式导出。 海底成像作业于2018年10月在RSS Discovery号船上开展，采用英国国家海洋学中心（UK National Oceanography Centre）研发的HyBIS遥控水下机器人（Remotely Operated Vehicle，ROV）。HyBIS为作业深度可达6000 m的遥控水下机器人，通过连接母船的光纤线缆进行控制，搭载两台Super Scorpio高清摄像机与一台索尼（Sony）HDR-CX560V型摄像机（Murton et al., 2012）。本次HyBIS下潜任务旨在基于多波束数据分析结果，对高关注度区域开展勘测与取样。本次勘测的水深范围为620 m至1480 m。ROV数据解译通过对勘测后全部视频录像的目视分析完成，目标为识别并解译数据中记录的主要地貌与海底侵蚀构造。