Ocean Structure and
Circulation
1
Ocean Model
Temperature
Warmer
Depth
Surface
Colder
Deeper
2
Ocean Model
3
Ocean Model
“Warm” shallow surface layer
Transition Zone
Cold deep layer
How do the layers form?
4
Surface
Layer
Transition
Zone
Homogeneous Ocean
Deep
Water
5
Taking the Temperature
C
Conductivity
TTemperature
D
Depth
www.soest.hawaii.edu
6
Ocean Temperature
Surface Layer
Thermocline
= Temperature
Transition
Zone Change
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?
7
Because of Density
Mass per unit volume
hawaiianphotos.net
Denser
3 3
1020-1028
19,300 kg/m
kg/m
Slashfood.com
Lighter
1000
100 kg/m
kg/m33
8
Ocean Density
Surface Layer
Pycnocline
Transition
Zone
Pycnocline
= Density
Change
Deep Water
• Seawater density is
controlled by Temperature
and Salinity
•In the ocean, Temperature
has a greater effect on
density
windows.ucar.edu
9
Surface
Layer
Transition
Zone
Thermocline
& Pycnocline
Boundary
Deep
Water
10
Warmed and lit by sun
Mixed
Surface
Layer
Boundary
Photosynthesis
Less Nutrients
Cold, Dark, No Photosynthesis , More Nutrients
Deep
Water
11
Summary
•
•
•
•
Surface Ocean
Warm
Lit by the sun
Has photosynthesis
Less nutrients
Deep Ocean
•
•
•
•
Cold
Dark
No photosynthesis
More Nutrients
12