What’s current with the ocean?

Catch my drift?

Currents move water from place to place

There are 2 kinds of currents…

First kind of current:1.Surface currents: move

on or near surface of ocean• Friction between wind blown

air and the water surface causes the water to move

• Controlled by wind belts, earth’s rotational effect and location of continents

What direction do most currents NORTH of the equator move?

CLOCKWISE!

What direction do most currents SOUTH of the equator move?

COUNTERCLOCKWISE!

• Western side of ocean has warm currents traveling from equator

• Eastern side of ocean has cool currents moving toward equator

Examples of warm water currents:• Gulf Stream• Brazil

Examples of cold water currents:• California current• Canary current

Upwelling• the rise of cold water from deeper layers to replace warmer surface water.

• brings greater concentrations of dissolved nutrients, such as nitrates and phosphates, to the ocean surface.

Second kind of current:

2. Deep density currents: cold, dense currents that flow very slowly beneath surface of ocean• occurs when denser

seawater moves towards an area of less dense seawater

• In the deep ocean, denser water around the Poles sinks and travels along the ocean floor toward the equator.

• At the same time, less dense water at the equator rises and moves towards the poles along the surface.

• These two events form a continuous cycle that circulate ocean water.

Waves

Kelly Slater

Wave Generating forces• WIND• TIDES• Sometimes Earthquakes

Wavelength•Distance from one crest to another

Wave Height•Difference between crest to trough

Period:•The time it takes one wavelength to pass a given point

Formula

Speed= wavelength period

Test your knowledge…

What is the speed of a wave 24 meters long with a period of 4 seconds?

Applying the formula

Speed = 24 meters= 6 meters/sec 4 sec

Height of wind-formed waves depends on 3 things…

1. Length of time the wind blows2. Speed of wind3. FETCH: length of open water

over which the wind blows in a single direction

Swells• Group of long, rolling waves all

about the same size• Come at regular intervals

• As waves approach shore, the water is so shallow that they touch bottom. This happens at a depth of one-half the wavelength. As the wave scrapes bottom, the lower part of wave slows down and upper par moves ahead. The crest falls over and breaks onto the beach.

Breaking Waves

MAVERICKS

Waves and the shore:• Breakers – foamy mass of water that

washes onto shore• Undertow• Long shore current• Tsunamis• Rip current – strong surface currents

that flow away from the beach; hazard to swimmers