There are five major ocean-wide gyres—the North Atlantic, South Atlantic, North Pacific, South Pacific, and Indian Ocean gyres. Each is flanked by a strong and narrow “western boundary current,” and a weak and broad “eastern boundary current” (Ross, 1995).

There are two kinds of current electricity: direct current (DC) and alternating current (AC). With direct current, electrons move in one direction. Batteries produce direct current. In alternating current, electrons flow in both directions.

The two basic types of currents – surface and deep-water currents – help define the character and flow of ocean waters across the planet.

There are two type of Ocean Currents:

• Surface Currents–Surface Circulation.
• Deep Water Currents–Thermohaline Circulation.
• Primary Forces–start the water moving.
• The primary forces are:
• Secondary Forces–influence where the currents flow.
• Solar heating cause water to expand.

Winds, water density, and tides all drive ocean currents. Coastal and sea floor features influence their location, direction, and speed. Earth’s rotation results in the Coriolis effect which also influences ocean currents.

Antarctic Circumpolar Current

Saltstraumen is the most powerful maelstrom in the world. The water speed has been measured at over 20 knots, and more than 3,000 m3 of water flow across the entrance to the fjord every second. Saltstraumen is very rich in fish, some of which are famously big.

If it continues to slow, that could have profound consequences for Earth’s inhabitants. Studies suggest it would mean much colder winters and hotter summers in Europe, changing rainfall patterns in the tropics, and warmer water building up along the U.S. coast that can fuel sea level rise and destructive storms.

Most down currents lose strength the deeper they go, but don’t just wait for the ride to end, though, as there’s no telling how deep the current will take you. If you get caught in a down current, try to remain calm.

No large standing bodies of liquid water exist on the planet’s surface, because the atmospheric pressure there averages just 600 pascals (0.087 psi), a figure slightly below the vapor pressure of water at its melting point; under average Martian conditions, pure water on the Martian surface would freeze or, if heated …

Arctic Ocean

You can see on the map of the major surface ocean currents that the surface ocean currents create loops called gyres (Figure below). The Antarctic Circumpolar Current is unique because it travels uninhibited around the globe. Why is it the only current to go all the way around? The ocean gyres.

The currents usually move at 1 to 2 feet per second (0.3 to 0.6 meters per second), but stronger ones can pull at 8 feet per second (1.6 meters/second).

Undertows occurs as wave breaks on the shore. The steeper that incline and the stronger the wave, the greater the undertow. In case you’re not aware, thats what a wave ‘sucking dry’ looks like. Certainly large enough waves on a steeply inclined shore could drag you under with a life jacket on.

2 to 3 knots

Rip currents are generally no wider than about 15 m (16.4 yards), so you only need to swim a short distance to try and get out of the current. Once out of it, you should be able to stand up and make your way back to shore in the areas where you can see breaking waves.

Rip currents are surface currents, not undertows. But while rip currents can move fast, they won’t take you far off shore. If you find yourself floating away from shore, try to relax, float, and wave for help. Myth: If you get caught in a powerful rip, you can be swept out to sea forever.

swim parallel. The best way to survive a rip current is to stay afloat and yell for help. You can also swim parallel to the shore to escape the rip current. This will allow more time for you to be rescued or for you to swim back to shore once the current eases.

In a rip current, death by drowning occurs when a person has limited water skills and panics, or when a swimmer persists in trying to swim to shore against a strong rip current, and thus eventually becomes exhausted and drowns.

Rip current speeds are typically 2 to 3 feet per second and extend about 200 feet offshore. RIPTIDES A riptide (or rip tide) is a powerful current caused by the tide pulling water through an inlet along a barrier beach. Riptides also occur in constricted areas in bays and lagoons where there are no waves.

You can help someone caught in a rip current by:

1. If you see someone in trouble, get help from a lifeguard.
2. If no lifeguard is available, have someone call 9-1-1.
3. Throw the rip current victim something that floats – a lifejacket, a cooler, a ball.
4. Yell instructions on how to escape.
5. Many have died trying to help others.