Tide and current data is available from NOAA's Center for Operational Products and Services website

Tides Tide Predictions. Generate a graphical display or a tabular listing of daily high and low tide predictions for more than 3,000 locations around the nation. Predictions may be generated up to two years in advance.

Real-Time Tide Data. Access current water levels from over 3,000 tidal stations. For the Great Lakes region, see Great Lakes Real-Time Water Level Data.

Historic Tide Data. For a given NOAA tide station, retrieve historic tide data from the earliest to the most recent dates for which data is available. For the Great Lakes region, see Great Lakes Historic Water Level Data.

Sea Levels. View a global map depicting regional trends in sea level, with arrows representing the direction and magnitude of change.

Tides Online. Choose a tide station by state and location to view current tidal information, wind speeds, air pressure, and air temperature. For the Great Lakes region, visit Great Lakes Online.

Tsunami-Capable Tide Stations. Access high resolution, one-minute water level sample data used to support national tsunami warning and mitigation efforts.

Tide Station Index. Generate a per-state list of all NOAA tide stations, including station number, name, location, installation date, and more.

Tidal Datums. Access NOAA's tidal datums. Scientists use datums to define "normal" water levels as a starting point from which all measurements are made. The numbers that appear on a nautical chart represent water depths measured relative to such a datum.

Currents Real-Time Current Data. View real-time current data collected by NOAA current meters around the nation.

Historic Current Data. View historic current data collected by active and retired NOAA current meters around the nation.

Tidal Current Predictions. Obtain tidal current predictions for more than 2700 tidal current stations nationwide.

Other CO-OPS Products and Services PORTS®. NOAA's Physical Oceanographic Real-Time System (PORTS®) improves the safety and efficiency of maritime commerce and coastal resource management through the integration of real-time environmental observations, forecasts and other geospatial information. PORTS® measures and disseminates observations and predictions of water levels, currents, salinity, and meteorological parameters (e.g., winds, atmospheric pressure, air and water temperatures) that mariners need to navigate safely in and around key maritime ports around the nation.

NowCOAST. NowCOAST is a web mapping portal that provides spatially referenced links to thousands of real-time coastal observations and NOAA forecasts of interest to the marine community.

Storm QuickLook. Access near real-time oceanographic and meteorological observations at locations affected by a tropical cyclone.

Operational Forecast System. This service offers nowcasts and short-term forecasts for select regions (critical ports, harbors, estuaries, Great Lakes, and coastal waters). These real-time observations and forecasts deliver present and future states of water levels, along with currents and other relevant oceanographic variables, such as salinity and temperature.

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The ocean is a huge body of water that is constantly in motion. General patterns of ocean flow are called currents. Sometimes theses currents can pinch off sections and create circular currents of water called an eddy.

You may have seen an eddy if you've ever gone canoeing and you see a small whirlpool of water while you paddle through the water. The swirling motion of eddies in the ocean cause nutrients that are normally found in colder, deeper waters to come to the surface.

Significant eddies are assigned names similar to hurricanes. In the U.S., an oceanographic company called Horizon Marine assigns names to each eddy as they occur. The names follow chronologically along with the alphabet and are decided upon by staff at Horizon Marine. The staff try to think of creative ways to assign names.

For example, an eddy that formed in the Gulf of Mexico in June 2010 is named Eddy Franklin after Ben Franklin, as he was known to have done research on the Gulf Stream.

For more information:
Ocean Mesoscale Eddies, NOAA's Geophysical Fluid Dynamics Laboratory
Center for Operational Oceanographic Products and Services
National Current Observation Program
Currents Tutorial, NOS Education
Diving Deeper Podcast, Episode 15 (August 12, 2009) - What are currents?
Horizon Marine

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With predicted, real-time, and forecasted currents, people can safely dock and undock ships, maneuver them in confined waterways, and safely navigate through coastal waters. This helps to avoid ship collisions or delay the arrival of goods.

In addition, current measurements are important for search and rescue operations, environmental disasters, and coastal engineering projects.

When supporting search and rescue operations, understanding the speed and direction of the currents in an area helps to narrow down the rescue and recovery effort. Current prediction information can help scientists clean up after a hazardous oil spill by helping them understand the direction and movement of the oil. Engineers also use currents information to help build marine structures such as bridges or docks and piers.

Current observations are also used to develop and evaluate coastal nowcast or forecast model products that are provided online.

For more information:
Center for Operational Oceanographic Products and Services
Currents (Diving Deeper podcast, 8.12.09)
NOS Education: Currents Tutorial
Tides (Diving Deeper podcast, 4.8.09)
NOS Education: Tides Tutorial



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The loop current is an area of warm water that travels up from the Caribbean, past the Yucatan Peninsula, and into the Gulf of Mexico. The current is also known as the Florida current as it flows through the Florida Strait, into the Gulf Stream, and heads north up the eastern coast of the U.S.

From the south, the Gulf of Mexico is fed by a current of warm water from the Caribbean, which enters the Gulf between Mexico's Yucatan Peninsula and Cuba. This forms the Gulf Loop Current, which curves east and south along Florida's coast and exits through the Straits of Florida.

The Gulf Loop is variable. Sometimes, the current barely enters the Gulf of Mexico before heading towards the Atlantic. At other times, it may travel nearly to the coast of Louisiana before swinging back towards the Florida Strait.

For more information:
Center for Operational Oceanographic Products and Services
National Current Observation Program
Diving Deeper Podcast, Episode15 (August 12, 2009) - What are currents?
Currents Tutorial, NOS Education

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An observer stands on a ship, throws the drifter into the water, and then measures the time that it takes that object to move along the side of a ship. As technology improved over time, oceanographers began using mechanical current meters. A ship would deploy a meter and usually some sort of rotor would turn and measure the currents. This is still the basic process today; however there are more accurate and sophisticated instruments.

Today in the open ocean, a drifter is similar to a buoy in the water that may be equipped with global positioning system technology or satellite communications that would relay data and information. Drifters can also submerge for long periods of time to measure ocean currents at a particular depth. The drifter would then resurface occasionally to send a signal with its data and position to observers on the land.

In addition to buoys, there are other tools that are used to monitor currents. The Acoustic Doppler Current Profiler is commonly used to measure currents. It is normally deployed on the sea floor or attached to the bottom of a boat. It sends an acoustic signal into the water column and that sound bounces off particles in the water. The instrument can calculate the speed and direction of the current by knowing the frequency of the return signal, the distance it traveled, and the time it took for the signal to travel.

Many oceanographers also use radio antennas and high frequency Radio Detecting and Ranging systems (radar) to measure surface ocean currents. Similar to the Acoustic Doppler Current Profiler, these shore-based instruments use the Doppler effect to determine when currents are moving toward or away from the shore or to measure the velocity of a current.

At NOAA, oceanographers use knots to measure current speed. The term knot is defined as one nautical mile per hour. One nautical mile is equal to 1.85 kilometers (1.15 standard miles). One knot is also 51.44 centimeters per second (3.281 feet per minute).

For more information:
Center for Operational Oceanographic Products and Services
National Current Observation Program
Diving Deeper Podcast, Episode15 (August 12, 2009) - What are currents?
Currents Tutorial, NOS Education

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Turbidity is a measure of the level of particles such as sediment, plankton, or organic by-products, in a body of water. As the turbidity of water increases, it becomes denser and less clear due to a higher concentration of these light-blocking particles.

Turbidity currents can be set into motion when mud and sand on the continental shelf are loosened by earthquakes, collapsing slopes, and other geological disturbances. The turbid water then rushes downward like an avalanche, picking up sediment and increasing in speed as it flows.

Turbidity currents can change the physical shape of the sea floor by eroding large areas and creating underwater canyons. These currents also deposit huge amounts of sediment wherever they flow, usually in a gradient or fan pattern, with the largest particles at the bottom and the smallest ones on top.

NOAA scientists use current meters attached with turbidity sensors to gather data near underwater volcanoes and other highly active geological sites. Also, satellite imagery is used to observe turbidity by measuring the amount of light that is reflected by a section of water.

For more information:
Ocean Geologic Features (pdf, 2Mb), NOAA Ocean Explorer
Ocean Turbidity, NOAA Coastal Services Center

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Although first observed in 1513 by Ponce de Leon, the Gulf Stream was not charted until the early 1770s by Benjamin Franklin, with the help of a Nantucket sea captain.

Around 1770, the Board of Customs in Boston, Massachusetts, noticed that packets travelling between Falmouth, Massachusetts, and New York, New York, by sea took two weeks longer to arrive than merchants travelling from London to Rhode Island. This was perplexing as Falmouth and New York were less than a day apart by road.

Franklin spoke with a sea captain who told him that while fishing for whales, he noticed that the whales would swim alongside the Gulf Stream, but never in it. Fishermen would frequently cross the Gulf Stream, where they passed packet ships sailing within, against the current. This was the reason for the delays. Franklin had the captain mark the location of the Gulf Stream, as well as the directions of its currents.

In 1843, the United States Coast Survey, NOAA’s earliest “ancestor”, set out to study the Gulf Stream in more detail. They wanted to determine the depth of the water, the temperature of the water at different depths, the characteristics of the ocean bottom, the direction and velocity of the currents at different depths, and the extent of plant and animal life. Their early observations led them to discover features such as cool and warm water banding, as well as the “Charleston Bump.”

For more information:
History of Ocean Exploration: Early Years (1807-1865), NOAA Ocean Explorer
1785: Benjamin Franklin's 'Sundry Maritime Observations', NOAA Ocean Explorer

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Rip currents are powerful, narrow channels of fast-moving water that are prevalent along the East, Gulf, and West coasts of the U.S., as well as along the shores of the Great Lakes.

Moving at speeds of up to eight feet per second, rip currents can move faster than an Olympic swimmer.

Panicked swimmers often try to counter a rip current by swimming straight back to shore—putting themselves at risk of drowning because of fatigue.

Lifeguards rescue tens of thousands of people from rip currents in the U.S. every year, but it is estimated that 100 people are killed by rip currents annually. If caught in a rip current, don't fight it! Swim parallel to the shore and swim back to land at an angle.

While the terms are ofter confused, rip currents are different than rip tides. A rip tide is a specific type of current associated with the swift movement of tidal water through inlets and the mouths of estuaries, embayments, and harbors.

For more information:
NOAA Rip Current safety tips, surf forecasts
Coastal Currents Education Kit, NOS Education
Rip Current photos

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The Kuroshio Current, in the Pacific off the east coast of Taiwan extending northward off the east coast of Japan, is the ocean's largest current. It can travel between 40-121 kilometers per day (25-75 miles per day) at speeds between 1.6-4.8 kilometers per hour (about 1-3 miles per hour) and extends some 1,006 meters ( 3,300 feet) deep.

Ocean currents are driven by wind, temperature changes, and tides

Oceanic currents are driven by three main factors:

1. The rise and fall of the tides. Tides create a current in the oceans, near the shore, and in bays and estuaries along the coast. These are called "tidal currents." Tidal currents are the only type of currents that change in a very regular pattern and can be predicted for future dates.

2. Wind. Winds drive currents that are at or near the ocean's surface. These currents are generally measured in meters per second or in knots (1 knot = 1.85 kilometers per hour or 1.15 miles per hour). Winds drive currents near coastal areas on a localized scale and in the open ocean on a global scale.

3. Thermohaline circulation. This is a process driven by density differences in water due to temperature (thermo) and salinity (haline) variations in different parts of the ocean. Currents driven by thermohaline circulation occur at both deep and shallow ocean levels and move much slower than tidal or surface currents.

Currents affect the Earth's climate by driving warm water from the Equator and cold water from the poles around the Earth. The warm Gulf Stream, for instance, brings milder winter weather to Bergen, Norway, than to New York, much further south. It keeps the Norwegian coast an incredible 6.1 degrees Celsius (43 degrees Fahrenheit) warmer than other places equally far north.

Most ocean currents flow in one direction all the time. In the northern Indian Ocean, though, they change direction twice a year, driven by the monsoon winds. From November to March, the currents are blown towards Africa by the cool, dry north-east monsoon winds. In May, the winds blow in the opposite direction, driving the water towards India.

For more information:
Observations of the Gulf Stream, NOAA Ocean Explorer
NOAA CoastWatch
Tides & Currents: Center for Operational Oceanographic Products and Services
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The Gulf Stream is an intense, warm ocean current in the western North Atlantic Ocean. It moves north along the coast of Florida and then turns eastward off of North Carolina, flowing northeast across the Atlantic.

Off the Atlantic seaboard of the United States, the Gulf Stream flows at a rate nearly 300 times faster than the typical flow of the Amazon River. The velocity of the current is fastest near the surface, with the maximum speed typically about 5.6 miles per hour (nine kilometers per hour). The average speed of the Gulf Stream, however, is four miles per hour (6.4 kilometers per hour). The current slows to a speed of about one mile per hour (1.6 kilometers per hour) as it widens to the north.

The Gulf Stream transports nearly four billion cubic feet of water per second, an amount greater than that carried by all of the world's rivers combined. For more information:
Observations of the Gulf Stream, NOAA Ocean Explorer
NOAA CoastWatch

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