The Nature of Oceans

1
The Nature of Oceans

• EarthComm Fluids
• Pages 7-11

2
Oceans of the World

• There are 4 large oceans on Earth (Atlantic,
  Pacific, Indian, Antarctic)
• All oceans have land borders (continents), but
  all oceans are connected to each other
• About 70 of the Earths surface is covered by
  water.

Atlantic
Pacific
Pacific
Indian
Antarctic
Antarctic
3
Oceans of the World (Continued)

• The open ocean is very deep average depth 4-5
  km
• Near the bottom of the ocean it is dark, cold,
  and has very high pressure

Dark deep ocean floor
Ocean floor in shallow waters
4
Ocean zones and Depths
5
The Warm and the Cold Ocean

• The ocean is layered by temperature
• Upper layer warmer water as high as 25oC
  (77oF)
• Lower layer colder water near 0oC (near
  32oF)

6
The Warm and the Cold Ocean

• Temperature of water decreases sharply between
  200m and 1000m below surface

7

• Thermocline the zone of rapid change from warm
  water to cold water with increasing
  depth in the ocean
• ? Similar to temperature difference noticed
  while treading water (top warmer, near feet
  colder)

8

• Pycnocline a layer of water in the ocean
  characterized by a rapid change of density with
  depth
• ? Density of ocean water increases as the
  temperature decreases (toward floor)
• ? Density of ocean water decreases as the
  temperature increases (toward surface)
• The thermocline and pycnocline happen to be
  approximately the same thickness in salt water
  due to the temperature and density
  characteristics

9
The Warm and the Cold Ocean

• Density changes as depth and temperature of the
  water changes.

10
Circulation of Oceans

• The layer above the thermocline is continuously
  circulating (moving)
• The deeper cold part of the ocean is continuously
  circulating

11
Circulation of Oceans (Continued)

• The circulations are different in nature
• Oceanographers scientists who study the Earths
  oceans
• ? They have come up with many theories to
  account for the circulation of the
  oceans, and they continue to work on the
  complicated problem

12
The Wind Stress
Wind direction

• Upper layer circulation is caused mainly by wind
  stress
• Wind Stress the frictional force exerted on the
  ocean surface by wind
• The blowing wind causes waves on the waters
  surface

13
The Wind Stress (Continued)

• As the waves get larger the wind has more effect
  on them
• Waves can cause problems
• a. Shoreline erosion b. Hazards
  to ships

14
The Coriolis Effect

• Water in the ocean moves in straight lines once
  set in motion
• Earth rotates underneath the moving water which
  actually causes the water to move in a curved
  path
• ? Coriolis force the apparent force caused by
  the Earths rotation which serves to deflect a
  moving body on the surface of the Earth
• The overall circulation of the oceans depends on
  the Coriolis effect

15
(No Transcript)
16
(No Transcript)