Ocean Structure and Circulation

1
Ocean Structure and Circulation
2
Ocean Model
Temperature
Surface
Depth
Deeper
3
Ocean Model
4
Ocean Model
Warm shallow surface layer
Transition Zone
Cold deep layer
How do the layers form?
5
Surface Layer
Transition Zone
Homogeneous Ocean
Deep Water
6
Taking the Temperature
Conductivity Temperature Depth
C T D
www.soest.hawaii.edu
7
Ocean Temperature
Surface Layer
Thermocline Temperature Change
Transition Zone

• Deep Water
• 90 of the total volume of ocean is this cold,
  deep water.
• At depths greater than 1000m, temperature is
  approximately 4ºC (even in the tropics!!).

windows.ucar.edu
Why do layers form?
8
Because of Density
Mass per unit volume
Lighter 1000 kg/m3
Denser 1020-1028 kg/m3
Lighter 100 kg/m3
Denser 19,300 kg/m3
9
Ocean Density
Surface Layer
Pycnocline Density Change
Transition Zone
Pycnocline

• Deep Water
• Seawater density is controlled by Temperature
  and Salinity
• In the ocean, Temperature has a greater effect on
  density

windows.ucar.edu
10
Surface Layer
Transition Zone
Thermocline Pycnocline
Boundary
Deep Water
11
Warmed and lit by sun
Mixed
Photosynthesis
Surface Layer
Less Nutrients
Boundary
Cold, Dark, No Photosynthesis
, More Nutrients
Deep Water
12
Summary

• Surface Ocean

• Deep Ocean

• Warm
• Lit by the sun
• Has photosynthesis
• Less nutrients

• Cold
• Dark
• No photosynthesis
• More Nutrients