INSS INFOMAR Seabed Samples

Research ships working at sea map the seafloor. The ships collect bathymetry data. Bathymetry is the measurement of how deep the sea is. Bathymetry is the study of the shape and features of the seabed. The name comes from Greek words meaning "deep" and “measure". Backscatter is the measurement of how hard the seabed is.

Bathymetry and backscatter data are collected on board boats working at sea. The boats use special equipment called a multibeam echosounder. A multibeam echosounder is a type of sonar that is used to map the seabed. Sound waves are emitted in a fan shape beneath the boat. The amount of time it takes for the sound waves to bounce off the bottom of the sea and return to a receiver is used to find out the water depth. The strength of the sound wave is used to find out how hard the bottom of the sea is. A strong sound wave indicates a hard surface (rocks, gravel), and a weak signal indicates a soft surface (silt, mud). The word backscatter comes from the fact that different bottom types “scatter” sound waves differently.

Using the equipment also allows predictions as to the type of material present on the seabed e.g. rocks, pebbles, sand, mud. To confirm this, sediment samples are taken from the seabed. This process is called ground-truthing or sampling.

Grab sampling is the most popular method of ground-truthing. There are three main types of grab used depending on the size of the vessel and the weather conditions; Day Grab, Shipek or Van Veen Grabs. The grabs take a sample of sediment from the surface layer of the seabed. The samples are then sent to a lab for analysis. Particle size analysis (PSA) has been carried out on samples collected since 2004. The results are used to cross-reference the seabed sediment classifications that are made from the bathymetry and backscatter datasets and are used to create seabed sediment maps (mud, sand, gravel, rock).

Sediments have been classified based on percentage sand, mud and gravel (after Folk 1954).

This dataset show locations that have completed samples from the seabed around Ireland. The bottom of the sea is known as the seabed or seafloor. These samples are known as grab samples. This is a dataset collected from 2001 to 2019.

It is a vector dataset. Vector data portrays the world using points, lines and polygons (areas).

The sample data is shown as points. Each point holds information on the surveyID, year, vessel name, sample id, instrument used, date, time, latitude, longitude, depth, report, recovery, percentage of mud, sand and gravel, description and folk classification.

The dataset was mapped as part of the Irish National Seabed Survey (INSS) and INFOMAR (Integrated Mapping for the Sustainable Development of Ireland’s Marine Resource). Samples from related projects are also included: ADFish, DCU, FEAS, GATEWAYS, IMAGIN, IMES, INIS_HYRDO, JIBS, MESH, SCALLOP, SEAI and UCC.

科研船在海上开展作业，进行海底测绘并采集水深测量（bathymetry）数据。水深测量是对海水深度的测量，同时也是对海底形态与特征的研究，其名称源自希腊语中意为“深”与“测量”的词汇。反向散射（backscatter）则是对海底硬度的测量。

水深测量与反向散射数据均由海上作业船只采集，这类船只使用名为多波束测深仪（multibeam echosounder）的专用设备。多波束测深仪属于声呐（sonar）的一类，用于海底测绘：设备会向船底下方扇形发射声波，通过声波从海底反弹返回接收器所需的时长计算海水深度，同时利用声波强度判断海底硬度——强声波信号对应硬质海底（如岩石、砾石），弱信号则对应软质海底（如粉砂、淤泥）。反向散射这一术语的由来，正是由于不同海底类型对声波的散射效果存在差异。

借助该设备还可预测海底表层物质类型，例如岩石、卵石、砂质与淤泥。为验证预测结果，需采集海底沉积物样本，这一过程被称为实地校验（ground-truthing）或采样。

抓斗采样（grab sampling）是最常用的实地校验方法。根据作业船只的规模与海况条件，通常使用三类抓斗：Day Grab、Shipek抓斗与Van Veen抓斗。抓斗可采集海底表层的沉积物样本，随后将样本送至实验室开展分析。自2004年起，科研人员已对采集的样本开展粒度分析（Particle size analysis, PSA），分析结果用于交叉验证基于水深测量与反向散射数据集得到的海底沉积物分类结果，并用于绘制海底沉积物分布图（涵盖淤泥、砂质、砾石与岩石四类）。

沉积物分类基于砂、淤泥与砾石的占比，分类标准参考Folk 1954年提出的方案。

本数据集收录了爱尔兰周边海域已完成海底沉积物采样的点位信息。海底又称海床，这类采样即为抓斗采样（grab samples）。本数据集的采样时间跨度为2001年至2019年。

本数据集属于矢量数据集，矢量数据通过点、线与多边形（面域）来表征地理空间信息。

采样数据以点要素形式呈现，每个点包含如下信息：调查编号（surveyID）、采样年份、作业船名称、样本编号、使用的仪器、采样日期、采样时间、纬度、经度、水深、采样报告、回收率、淤泥/砂质/砾石占比、样本描述以及Folk分类结果。

本数据集是爱尔兰国家海底调查（Irish National Seabed Survey, INSS）与INFOMAR（爱尔兰海洋资源可持续发展综合测绘计划，Integrated Mapping for the Sustainable Development of Ireland’s Marine Resource）项目的组成部分，同时收录了相关项目的采样数据，包括ADFish、DCU、FEAS、GATEWAYS、IMAGIN、IMES、INIS_HYRDO、JIBS、MESH、SCALLOP、SEAI以及UCC等项目。