Movement of Water in the Oceans

What are Ocean Waves? Ocean Waves are the large scale movement of energy through water molecules. The wave energy moves forward, the molecules don’t. They just move in a circular motion

Think of surfers waiting for a wave, they bob up and down, but don’t travel forward as a wave (and its energy) passes beneath them. They have to kick, paddle, or be towed into a wave to ride it. Video of circular motion of a water molecule, it appears to just bob up and down.

How do ocean waves form? Most waves develop on the surface of the water by a disturbance such as wind. Friction between the air and water causes the wind to pull the water upward while gravity works to pull the water back down.

Wave height Wave height is determined by three things How long the wind has been blowing How much open water the wind is blowing across (fetch) The speed of the wind Making waves interactive simulator

Fetch is happening!

Breaking waves Eventually a wave stops growing in size, and it will break.

When waves approach shore the water depth decreases and the wave will start feeling the bottom. As the wave feels the bottom, the circular loops of water motion change to elliptical shapes, as loops are deformed by the bottom. Eventually the steep front portion of wave cannot support the water as the rear part moves over, and the wave breaks.

Review of the formation of a wave ?p=how+does+an+ocean+wave+form&vid=76910b320e5d940b90f90547a11fa9b8&l=2%3A44&turl=http%3A%2F%2Fts3.mm.bing.net%2Fth%3Fid%3DVN %26pid%3D15.1&rurl=http%3A%2F%2Fchannel.nationalgeographic.com%2Fchannel%2Fvideos%2Fdevelopment-of-ocean- waves%2F&tit=Development+of+Ocean+Waves&c=4&sigr=12go7cnld&sigt=10qelggjb&pstcat=arts+culture+and+entertainment&age=0&fr=mcafee&tt=b

You can use your knowledge of science (weather and wave formation) to find the perfect surf spot!

Why are waves usually larger on the west coast? More fetch Prevailing westerlies wind pattern Sudden reduction of water depth

Parts of a wave Crest – High point Trough – Low point Wave height – Distance from crest to trough Wavelength – Distance between crests

Parts of an ocean wave

Special Waves Tsunamis: Giant waves caused by seismic activity Most damaging waves travel over great distances Tsunami waves lose very little energy in the open water When encountering the shoreline, friction quickly slows the bottom of the wave, allowing water to rise quickly Tsunami waves do not have to be tall to be damaging, the surge of the amount of water is the issue!

Tsunamis form when energy from an underwater earthquake moves the water, rather than wind energy at the surface.

Tsunamis The wave will continue until it hits land

Some of the wave energy even reached the US.

Storm Surge A high water event associated with significant low pressure weather disturbances (hurricane, topical storms, etc.) Low Pressure systems allow sea levels to rise (high pressure depresses sea level) High winds push water inland

Storm Surge

“Rogue” Waves: “Rogue” Waves: Greater than twice the size of surrounding waves Unpredictable, may approach from opposite direction of normal waves Steep sided with deep troughs algeographic.com/cha nnel/alien- deep/videos/rogue- waves/?source=search video

Rogue wave in the Mediterranean in 2010

Surfing waves Surfing one of the world’s heaviest waves Look up current wave height data in different regions of earth

wave formation, slow but good visual explanation 3 min

Is the motion of the water caused by waves, currents, or tides? A review quiz

1. Water levels are higher than normal during a full moon. WaveCurrent Tide

2. A tsunami WaveCurrent Tide

3. A constant flow of cold water from Alaska travels all the way to California WaveCurrent Tide

4. Water moving an iceberg from Greenland to the N. Atlantic WaveCurrent Tide

5. A ring of moving water in a swimming pool after your friend does a cannonball in the deep end. WaveCurrent Tide

6. “Rivers” of water that flow in a specific direction. WaveCurrent Tide

7. Large, movement of water in a circular path called a gyre WaveCurrent Tide

8. In oceans, the movement of energy through the water WaveCurrent Tide

9. Water moving due to differences in density (cold and salty will sink) WaveCurrent Tide

10. These depend on the wind speed, distance wind traveled, and how long the wind was blowing WaveCurrent Tide

11. Type of water movement that can influence a local climate. WaveCurrent Tide

12. The large scale movement of water due to wind WaveCurrent Tide

13. Movement of water due to the moon and sun’s gravitational pull WaveCurrent Tide

14. Water in the Northern Hemisphere moves in a clockwise direction due to the Coriolis effect. WaveCurrent Tide

15. The up and down movement of water levels WaveCurrent Tide

16. Water motion pictured below: WaveCurrent Tide

17. Water motion pictured below: WaveCurrent Tide

18. Water motion pictured below: WaveCurrent Tide