Autonomous Underwater Vehicle (AUV) still images - Caswell Sub-basin, Browse Basin Marine Survey (GA0345/GA0346/TAN1411)

Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region.

The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core.

This catalogue entry refers to Autonomous Underwater Vehicle (AUV) still image data acquired during survey GA0345/GA0346/TAN1411.

Following mapping with the shipboard multibeam, higher-resolution multibeam data were acquired in targeted areas using a Kongsberg Simrad EM2000 system mounted to the Fugro Echo Surveyor V (ES-5) AUV. This instrument had a depth rating of 3000 m, and surveyed the seafloor according to a pre-programmed mission plan. The AUV was fitted with a camera and light system designed to produce images of equal width and height (in the context of this survey, the images comprised 8 m by 8 m of seafloor). The equipment consisted of a light sensitive NEO 11 Megapixel 35 mm monochrome CCD (4008 x 2672) camera and two LED panels, each comprising 360 LEDs. High-resolution multibeam bathymetric data was collected together with side scan sonar and sub bottom profile data at an elevation of 30 m above the seafloor, and at line spacing's of 100 m. Overlapping high-resolution still photographs (captured every second) were then acquired on the survey lines at an elevation of 8 m above the seafloor. The AUV was equipped with an advanced real-time Aided Inertial Navigation System, which calculated the position, velocity and altitude of the vehicle and a HiPAP 500 USBL system was used to acoustically position the AUV.

Underwater imagery was collected from two AUV missions in study Areas 3 and 4. During the 2nd AUV mission on 22 October, the vehicle encountered an obstruction on the seabed and became trapped despite commencing an emergency ascent sequence. The AUV was subsequently recovered from the seabed during salvage operations incorporated into the ROV phase of survey operations.
A total of 24 877 still images were acquired in Area 3 and 20 743 in Area 4 over 58 and 56 line kilometres, respectively. Still images (.jpg files) are located in folder 'TAN1411_AUV_STILLS' with sub-folders named according to gear code (AUV= Autonomous Underwater Vehicle), mission and study Area (e.g. AUV_M2_A3 = still images acquired during AUV mission 2 in Area 3). USBL (Ultra-short baseline) text files (`TileCam.idx) are located in each sub-folder and provide continuous navigational information on location, time (UTC) and depth of AUV still imagery transect lines.

澳大利亚地质调查局（Geoscience Australia, GA）于2014年10月9日至11月9日对东北布鲁克盆地（卡斯维尔次盆）开展海洋调查（航次编号GA0345/GA0346/TAN1411），旨在获取海底与浅部地质数据，支撑该盆地二氧化碳封存潜力评估。本次调查作为澳大利亚工业与科学部国家二氧化碳基础设施计划（National CO2 Infrastructure Plan, NCIP）的组成部分，目标是识别并表征天然烃类或流体渗漏的指示标志，以评估该区域盖层完整性是否遭到破坏。

本次调查由新西兰“坦加罗阿”号（RV Tangaroa）研究船分三个航段执行，参与单位包括澳大利亚地质调查局、新西兰国家水与大气研究所（National Institute of Water and Atmospheric Research Ltd., NIWA）及富格罗勘探私人有限公司（Fugro Survey Pty Ltd.）的科研与技术人员。航次数据（航次编号GA0345）采集内容涵盖12个区域（A1、A2、A3、A4、A6b、A7、A8、B1、C1、C2b、F1、M1）的多波束测深声呐与后向散射数据，覆盖面积达455平方千米，作业水深范围为90~430米，同时完成了611千米的浅地层剖面测量。本次调查共布设48个海底采样站位，采集样品包括99份史密斯-麦金太尔采泥器样品与41份活塞岩心。自主水下航行器（Autonomous Underwater Vehicle, AUV，航次编号GA0346）采集了更高分辨率的多波束测深声呐与后向散射数据，覆盖面积总计7.7平方千米，同时完成了71千米侧扫声呐、水下摄像与浅地层剖面测量作业。22次遥控水下机器人（Remotely Operated Vehicle, ROV）作业累计获取31小时水下视频、657张静态图像、8份采泥样品与1份岩心。

本目录条目对应本次调查（GA0345/GA0346/TAN1411）中采集的自主水下航行器静态图像数据。

在船载多波束测深作业完成后，项目组通过搭载于富格罗回声勘探者V号（Fugro Echo Surveyor V, ES-5）自主水下航行器的康士伯西姆拉德EM2000系统，在目标区域开展了高分辨率多波束数据采集。该系统作业深度极限为3000米，按照预编程任务计划完成海底勘测。该自主水下航行器搭载了专为获取等长宽海底图像设计的摄像与照明系统（本次调查中，单幅图像对应8米×8米的海底区域），设备包括一台NEO型1100万像素35毫米单色CCD相机（分辨率4008×2672）与两块各含360颗LED的照明面板。高分辨率多波束测深数据与侧扫声呐、浅地层剖面数据均在距海底30米的高度采集，测线间距为100米。随后，航行器在距海底8米的高度沿测线获取了每秒采集一张的重叠高分辨率静态照片。该自主水下航行器搭载了先进的实时辅助惯性导航系统，可计算航行器的位置、速度与高度，同时配备HiPAP 500超短基线（Ultra-short baseline, USBL）系统用于声学定位。

水下图像采集作业在研究区域3与区域4的2次自主水下航行器任务中完成。10月22日的第二次自主水下航行器任务中，航行器遭遇海底障碍物，尽管启动了紧急上浮程序仍被卡滞。后续该航行器在本次调查遥控水下机器人阶段的打捞作业中被成功回收。
本次作业在区域3与区域4分别完成24877张与20743张静态图像，对应测线长度分别为58千米与56千米。静态图像以JPEG（.jpg）格式存储，存放于“TAN1411_AUV_STILLS”文件夹下，子文件夹按设备代码（AUV=自主水下航行器）、任务与研究区域命名（例如AUV_M2_A3代表区域3中AUV任务2采集的静态图像）。每个子文件夹中均包含超短基线（USBL）文本文件`TileCam.idx`，用于提供自主水下航行器静态图像测线的位置、UTC时间与水深等连续导航信息。