Hydrographic Use of Satellite Imagery in South Pacific

The French Hydrographic Office (SHOM) uses remotely sensed visible imagery for the cartography of atolls and reefs. It is considered as an efficient and relatively inexpensive method to collect information where data is sparse. Remotely sensed visible imagery is used in Pacific French Overseas territories for the cartography of atolls, reefs et cetera. All shallow-water areas may be involved, in particular when the cost of usual hydrography would be out of proportion with maritime traffic. Remotely sensed imagery is mixed with all field information available (bathymetry, buoys, seamarks) and a ‘spatiocarte’ (spatio-chart) is produced, which provides information on: Land: coastline,... (read more)
2008-01-01 01:00:00

Successful Delivery of Coastal Survey Data to the Royal Australian Navy

IHO Order 1b Bathymetric Lidar Data
Amongst the largest contracted coastal hydrographic Lidar survey projects awarded in recent years is the Australian Hydrographic Service (AHS) survey of the Torres Strait in Northern Queensland. The intent of this very large survey was to update nautical charting in the region, facilitate safer navigation and enhance the capacity of maritime enforcement vessels to protect and secure Australian waters from incursions by illegal foreign fishing vessels. As it was to be used for international chart products, the survey data had to be of an accordingly high standard. Approximately 850km north from Cairns, the Torres Strait forms the confluence between the... (read more)
2010-05-31 10:44:08

Vision for a Better World: Integrated Coastal, Ocean and Earth Observation

Interview with Vice-Admiral C. Lautenbacher Jr., US Navy (Ret.)
A graduate of the US Naval Academy, Vice-Admiral Conrad C. Lautenbacher Jr. has masters and doctoral degrees in applied mathematics from Harvard University. Before joining NOAA he was president and CEO of CORE, the Consortium for Oceanographic Research and Education. As commander of US Naval Forces during Operations ‘Desert Shield’ and ‘Desert Storm’ he was responsible for Navy planning and participation in the air campaign and pioneered the use of information technology to mount large-scale operations using sea-based command and control. As not all our readers are familiar with US organisations, could you briefly describe CORE and NOAA? NOAA, the... (read more)
2008-01-01 01:00:00

Deepwater Survey, Investigation and Intervention

Survey, geotechnics and Remotely Operated underwater Vehicle (ROV) operations are all individually very interesting subjects as far as their exponents are concerned. But this combination, with the added dimension of working at an unusual work-site in extreme depths of water, has made the Prestige Project a very challenging programme for participants. In November 2002, whilst under tow in poor weather conditions, the Bahamas-flagged Prestige oil tanker broke in two and sank approximately 150 miles off the north west coast of Spain and Portugal in 3,800 metres (12,500 feet) of water. The two parts of the hull came to rest on... (read more)
2008-01-01 01:00:00

Improving the Accuracy of ADCP Discharge ­Measurements

Automating Edge Discharge Calculation in ADCP Software
There is a key new feature in the discharge measurement software ViSea DAS that allows the user to add a bottom profile. By doing so, side extrapolation from the start and end points of the survey track to the shore is calculated automatically using dGPS positioning. This removes the error inherent in estimating the track to shore distance for each individual track, which is the current method used in comparable software packages. This paper describes research that validates this new approach. Discharge measurements are important for the characterisation of rivers and are the basis of many models. There are many... (read more)
2014-05-19 02:19:44

How Google Explores the 10th Planet

About Mermaids and Sea Serpents
NASA has spent tens of billions of dollars exploring Planet Earth and the other eight planets of our solar system, yet there is one last great frontier that has gone almost completely unexplored – Planet Ocean. The disparity between our understanding of Planet Earth and Planet Ocean is highlighted by the computer program and image repository Google Earth. However, the ability to use Google Earth below sea level provides a new platform for scientists to exchange oceanographic information and also deliver research findings to the general public. Remote sensing satellites provide high-resolution imagery of all of Earth. Check out the... (read more)
2009-10-05 11:03:52

Embarked on Tsunami Disaster by Hydrographic Offices

International Workshop on Tsunami Inundation Mapping
An International Workshop on Tsunami Inundation Mapping was held in Tokyo, Japan on 25-26 November 2015, aiming to improve the capacity of Hydrographic Offices (HOs) in East Asian countries on the Tsunami Inundation Map (TIM). TIM is an important tool in increasing public awareness and making countermeasure  plans for an expected tsunami disaster. HOs are expected to contribute to the development of the TIM in their own states, because bathymetric information is essential for this. This event was the first of its kind in the international hydrographic community. By Hideki KINOSHITA and Norio BABA, JHOD, Japan The Indian Ocean tsunami, triggered... (read more)
2015-12-21 02:17:51

Ice-jam Floods

River Ice-jams cause Severe Flooding in Tom River, Western Siberia
The large, poleward flowing rivers of Siberia, such as the Ob River, experience persistent and severe floods when river ice breaks up in the spring. Ice-jams are common on the Tom River, a tributary of the Ob, resulting in a rapid rise in water levels upstream of the jam and submergence of thousands of homes. Sudden failure of the ice-jam releases a flood wave that can cause extensive damage downstream. Floods in large rivers are caused by a variety of processes. River flows may rise to flood levels at different rates, from a few minutes to several weeks, depending on... (read more)
2014-07-17 02:41:00

The Laboratory Measurement

Salinity is one of the most measured parameters in oceanography. The importance of high quality salinity data has long been recognised in open ocean studies and more recently in coastal and estuarine processes. Much data is collected using in-situ instrumentation (e.g. CTD, multi-probes) but the measurement of salinity in the laboratory remains an important and widely used technique. This article describes developments made to allow the high precision, accurate measurement of Practical Salinity in the laboratory. In recent years salinity data has provided important information in the study of climate change. Large transects of the ocean using CTD profiles have... (read more)
2008-01-01 01:00:00

ROVs as Versatile Workhorses

Many Tasks in Many Shapes and Sizes
The concept of ROVs does not seem to change too much over time. Basically, they are self-propelled instruments working in deep waters up to about 6,000m that are linked to a vessel-based controller. This distinguishes them from AUVs that move underwater without a tether to a vessel. As with any other machine, they are available in many shapes and types, evolving over time. With a hydrographer’s eye, we give an overview of the varieties available and the direction in which ROVS are moving. ROVs are available in different classes, which as such point to their main use. Observational, light work... (read more)
2015-04-03 01:22:45
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