Great Potential for SAS in Hydrography

Using Synthetic Aperture Sonar as an Effective Hydrographic Survey Tool
Synthetic Aperture Sonar (SAS) has been around for over a decade but its primary purpose has been in mine detection rather than hydrographic surveying. To use SAS effectively a stable survey platform is required such as an autonomous underwater vehicle (AUV). These platforms are becoming more commonly used in hydrographic surveying and as a result the viability of SAS as a survey sensor seems a logical progression for the industry with the suggested benefit of increased data quality, better resolution and a pathway to a more modern data-centric survey deliverable. SAS is a technique for creating high-resolution seabed reflectivity images... (read more)
2015-04-03 01:32:11

Global Sediment Observations for the Dredging Industry

Coastal engineering and dredging companies often require an assessment of the suspended sediment concentrations. At the project proposal stage, this information is needed to assess the amount of work to be done and the costs involved and once dredging or construction is underway, information on suspended matter concentrations may be required for monitoring the environmental impact of the dredging or construction work. ARGOSS has developed a new service to produce maps of suspended sediment concentrations, based on satellite remote sensing data. The service has been demonstrated successfully in the Berbice estuary, an area of slowly migrating mudbanks in Guyana, and... (read more)
2008-01-01 01:00:00

Technology in Focus: Acoustic Doppler Current Profilers (ADCP)

Widespread Applications Stem from Diverse Measurement Capabilities
Rather than a spinning propeller, the Acoustic Doppler Current Profiler (ADCP) – just like dolphins and bats – uses sound to explore its environment. Operating underwater, the method works like hand-held radars used by police to catch speeding motorists. This article explains the technique of this frequently used type of instrument and some of its applications. A sound burst is emitted by the ADCP along beams angled downward. Echoes are returned due to scattering off particles carried by water currents. A second burst can be used to track movement over the seabed. By analysing these sound echoes, the ADCP makes... (read more)
2017-01-25 08:53:33

The Drifters

“Although the Currents of the Ocean form a most important part of hydrography, yet it is only since the introduction of chronometers, and of celestial observations for the longitude at sea, (that is, not much more than forty years ago,) that a competent idea of their [currents] direction and force, in any kind of detail, could be obtained.” Thus wrote Major James Rennell in 1820 in the opening lines of his posthumously published (1832) An Investigation of the Currents of the Atlantic Ocean. Although the existence of oceanic currents had been known since the time of Columbus, the inability of... (read more)
2014-05-19 02:21:58

Nautical Depth Survey System

The Port Authorities in China want to adopt as standard in ports and harbours the navigable water depth; many ports in China have a problem with silt, liquid mud, deposited by rivers. Liquid silt has the characteristic of prohibiting navigation if it reaches a certain density. In most ports, silt with a density of 1,250kg/ltr and more is not navigable. The depth at which this density is found is called the Nautical Depth. To determine the Nautical Depth, instruments are needed to measure the density of the mud and to determine this datum for safe navigation and for dredging purposes.... (read more)
2008-01-01 01:00:00

Space-borne Technologies for the O&G Sector

From Operational Environmental Monitoring to Rapid Bathymetry Mapping
This article describes the methods, applications, services and validation of such projects, showcasing the possibilities of these technologies. Satellite-derived mapping and monitoring technologies can provide important support for a range of applications in the oil and gas industry. Satellite-derived mapping and monitoring technologies can provide important support for a range of applications in the oil and gas industry. Prior to tasks such as pipeline routing and other infrastructure engineering activities, these technologies can be efficiently deployed over large, remote and/or in-accessible areas for bathymetry charting, mapping seafloor habitats and monitoring the health of near coastal ecosystems. During dredging activities, satellite-derived... (read more)
2013-09-06 04:32:53

The European Seafloor Observatory Network (ESONET)

ESONET proposes a network of sea floor observatories around the European Ocean Margin, from the Arctic Ocean to the Black Sea, for strategic long-term monitoring as part of the European GMES (Global Monitoring for Environment and Security). The network will have capabilities in geophysics, geotechnics, chemistry, biochemistry, oceanography, biology and fisheries. Long-term data collection and alarm capability in the event of hazards (e.g. earthquakes) will be considered. Ten initial areas for ESONET development have already been identified, in addition to a mobile emergency response station. The submarine terrain around Europe, from the continental shelves to 4,000 m depth, is known... (read more)
2008-01-01 01:00:00

Approaches to Hydrographic Training and Capacity Building

Technology and Blended Learning for Flexible, Modular Training
The Challenge: To provide a stimulating educational framework that blends relevant theory with practical exercises without removing individuals from their work environment for too long a period and optimising investment in complex and expensive equipment that may only be used a few weeks per year. The IHO FIG/IHO/ICA International Board for Standards of Competence (IBSC) has recognised the need for the competency standards to continue to evolve to meet these contemporary and future requirements. This paper presents an approach taken to modernise the training and capacity building aspects of these challenges. The demands made upon the world’s charting authorities continue... (read more)
2013-07-12 02:15:09

Marine SDI

Introducing Spatial Data Infrastructures
Global warming, climate change, rising sea levels and increased commercial exploitation of the seabed and sea space are important global indicators of a changing world environment. A crucial role is played by hydrographic and oceanographic spatial data in supporting response. Accurate and timely base reference information minimally comprises seabed topography and characterisation to which temporal information such as wave, tide and current can be referenced. In order to provide a complete picture, information held by HOs, National Mapping Agencies (NMAs), geologists, biologists and oceanographers can be brought together to provide solutions through enabling frameworks known as Spatial Data Infrastructures (SDIs).... (read more)
2007-07-13 12:00:00

Trends and New Technology in the ROV Industry

New IMCA ROV Classifications and Applications Moving Towards Renewables
Over the past few years, the requirement for ROV support in the oil & gas sector has been hampered by the downturn in the sector. However, the continued investment in renewable energy has provided opportunities for manufacturers to continue their R&D projects to create the next generation of ROV systems. In view of this, the IMCA guidelines for the Safe and Efficient Operation of Remotely Operated Vehicles (IMCA R 004 Rev4) has been updated. The guidelines now include an expanded list of ROV classifications based upon the increased diversification of tasks performed by ROV systems around the globe. The revised... (read more)
2017-08-07 01:31:12
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