Versatile Tide Gauge

Valeport Ltd, UK, has introduced a seabed-mounted tide recorder that makes precise water level measurements where conventional units attached to piers and jetties are not practicable. Applications are in oceanography, hydrography and marine civil engineering projects. Called the MIDAS Tide Recorder, the new instrument is also designed to be part of an in-line mooring. The high accuracy (±0.01 per cent) pressure sensor and temperature sensor is housed in acetal rated to 1,000m water depth. The MIDAS Tide Recorder has a wide range of sampling regimes and rates. It can sample at 1, 2, 4 or 8Hz and can log/output data... (read more)
2003-10-25 12:00:00

RTK Tide Basics

One of the fastest emerging trends in hydrographic surveying is the use of the vertical component of RTK GPS to determine real-time water level corrections. There are currently several district offices of the US Army Corps of Engineers using this technique in place of conventional tide measurements.The main purpose of this article is to explain some of the basics behind the technique (without getting overly technical) and to point out some of the benefits and drawbacks to the method. The Basics Looking at Figure 1, let’s define the following terms: For simplicity, I am ignoring the heave-pitch-roll of the vessel... (read more)
2008-01-01 01:00:00

Bluetooth Tide Gauge

TideM8 is a combination of the Ohmex TideM8 miniature tide gauge system and Trimble's Juno hand-held Mobile PC with integrated GPS. The system is a new design based on the 'Winstrument' concept of an instrument using Bluetooth communications and Mobile PC equipment as the user interface.   Using the latest low power processor and flash memory technology, the new gauge design offers precise calendar and time-keeping functions together with solid state data retention. The internal data logging will retain up to ten years of data readings, each record containing time, date, average tide, water temperature, barometric pressure and wave range.... (read more)
2007-08-10 01:49:12

RTK Tide Basics

One of the fastest emerging trends in hydrographic surveying is the use of the vertical component of RTK GPS to determine real-time water level corrections. There are currently several district offices of the US Army Corps of Engineers using this technique in place of conventional tide measurements.The main purpose of this article is to explain some of the basics behind the technique (without getting overly technical) and to point out some of the benefits and drawbacks to the method. The Basics Looking at Figure 1, let’s define the following terms: For simplicity, I am ignoring the heave-pitch-roll of the vessel... (read more)
2008-01-01 01:00:00

Significant 2008 "Red Tide" Season

The end of April usually brings the first signs of harmful algae in USA's New England waters, and this year, researchers from the Woods Hole Oceanographic Institution (WHOI) and North Carolina State University (NC State) are preparing for a potentially big bloom.   A combination of abundant beds of algal seeds and excess winter precipitation have set the stage for a harmful algal bloom similar to the historic "red tide" of 2005, according to researchers from WHOI and NC State. The 2005 bloom shut down shellfish beds from the Bay of Fundy to Martha's Vineyard for several months and caused... (read more)
2008-04-29 01:14:44

Tide Models for Hydrographic Surveying

Computer models replace tide poles
Hydrographic surveying has become a highly sophisticated operation, with GPS for accurate fixing of position, acoustic technology for mapping the sea-bed either side of the survey vessel, and on-board computer systems to automatically process the data. But the corrections made for tide are in many cases still done using methods that date back to Captain Cook's days in the late 18th century. These methods may be adequate for places where the tide does not change much from place to place, or if the tidal range is small. But in places where the tide varies widely, the accuracy of tidal corrections... (read more)
2008-01-01 01:00:00

New Tide and Wave Recorder

RBR Ltd. has introduced the TWR-2050, a new compact submersible tide and wave recorder. The unit, with both burst modes and averaging, is capable of recording tide and wave data according to a flexible user-programmable deployment scheme. Low-power operation and a large internal flash memory provide characteristics for extended deployments. A simple connection to an RF modem or cellular link also makes this suitable for real-time monitoring of sea-state conditions. (read more)
2005-01-24 12:00:00

Permanent Tide Station for Dubai

Unique System FZE, a Unique Maritime Group Company, UAE, together with the Geodesy and Hydrographic Survey Section of Dubai Municipality has established a permanent tidal station at Al Mamzaar. The purpose of the project is to collect precise tide data continuously for a period of 19 years to calculate mean sea level and annual sea-level rise and to provide precise tide and tide-related meteorological data to various users, as well as to define and update a precise vertical datum for Dubai Emirate. Dubai Municipality’s Geodesy and Hydrographic Survey Section has several components comprising various sub-systems that provide real-time monitoring, alerts,... (read more)
2013-02-06 12:00:00

The Mexican Navy’s Tide Network

The DIRECCION GENERAL ADJUNTA DE HIDROGRAFIA Y CARTOGRAFIA (DIGADIHCAR) has a national tide and meteorology network. Transmission of data is done both by satellite communication and by telephone links to a central processing unit at a department of the DIGADIHCAR specialised in tidal data collection and analysis. This information is used not only for support of safety of navigation but also forms part of the system for timely obtaining, indicating and promulgation of meteorological and tidal information. This might concern, for example, severe storm warnings for the protection of human life at sea and amongst populations living in coastal areas.... (read more)
2008-01-01 01:00:00

Tide Prediction in Colonial America

Although tidal ranges in America are, in general, less than in Europe, they have still had an impact on history. Many harbours were only accessible with high tide, introducing a lunar influence on the maritime economy. However, misjudgement of tide levels also played a crucial role in several historical events, even hilarious ones as you can read about here when Bruce Parker describes the tide situation at the time of the Boston Tea Party.   In 1776, the same year that the American colonies declared their independence from Great Britain, Pierre Simon the Marquis de Laplace published a paper that... (read more)
2009-05-12 12:00:00
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