Tidal Streams,currents and their measurement
Tidal streams and currents are both movements of water in the ocean, but they have different causes and characteristics.
Tidal streams
are caused by the gravitational pull of the moon and sun on the Earth’s oceans. They are predictable and follow a regular cycle, with the direction and speed of the current changing with the tides. Tidal streams are strongest in coastal areas and estuaries, where the water is confined and the tidal range is high.
Currents
can be caused by a variety of factors, including wind, waves, and water temperature. They can be constant or variable in direction and speed, and they can occur anywhere in the ocean.
Measurement of tidal streams and currents
Tidal streams and currents can be measured using a variety of methods, including:
- Current meters: These instruments measure the speed and direction of the current at a specific point.
- ADCPs (Acoustic Doppler Current Profilers): These instruments use sound waves to measure the speed and direction of the current at different depths.
- Radar: Radar can be used to track the movement of surface currents.
- Satellite imagery: Satellite imagery can be used to track the movement of currents over large areas.
Importance of measuring tidal streams and currents
Measuring tidal streams and currents is important for a variety of reasons, including:
- Navigation: Tidal streams and currents can affect the speed and direction of ships, so it is important for mariners to know about them when planning their voyages.
- Offshore activities: Tidal streams and currents can affect the positioning and operation of offshore structures, such as oil platforms and wind turbines.
- Fisheries management: Tidal streams and currents can transport fish larvae and eggs, so it is important to understand them when managing fisheries.
- Coastal erosion: Tidal streams and currents can contribute to coastal erosion, so it is important to understand them when planning coastal protection measures.
Predicting tidal streams and currents
Tidal streams and currents can be predicted using a variety of mathematical models. These models take into account the gravitational forces of the moon and sun, the shape of the coastline, and the depth of the water.
Tidal stream and current predictions are available from a variety of sources, including government agencies, private companies, and websites. These predictions can be used by mariners, offshore operators, fisheries managers, and coastal planners.