|
|
|
Basic Structures |
|
Surface Ocean Circulation |
|
Deep Ocean Circulation |
|
|
|
|
Upper
Ocean (~100 m) |
|
Shallow, warm upper layer where light is abundant and where most
marine life can be found. |
|
|
|
Deep
Ocean |
|
Cold,
dark, deep ocean where plenty supplies of nutrients and carbon exist. |
|
|
|
|
|
|
|
|
Thermo è
temperature |
|
Haline è salinity |
|
|
|
|
|
|
|
|
|
|
Evaporation: Extremely cold, dry winter air enhances
evaporation from the relatively warm ocean è increase salinity in
the ocean. |
|
Formation
of Sea Ice: When sea ice forms, salts are left in the ocean è increase
salinity |
|
|
|
|
|
|
If we
date a water parcel from the time that it leaves the surface and sink into
the deep ocean |
|
|
|
è Then the youngest water is in the deep north
Atlantic, and the oldest water is in the deep northern Pacific, where its
age is estimated to be 1000 year. |
|
|
|
|
the
waters in the deep northern Pacific. |
|
The
concentration of nutrients is at a minimum in the deep northern Atlantic
because the water there has just arrived from the nutrient-depleted surface
layers. |
|
On its
subsequent journey, the water is then steadily enriched by sinking organic
materials and reaches it maximum concentration at the deep northern
Pacific. |
|
|
|
|
the
waters in the deep northern Pacific. |
|
The
man-released CFC and the chemical tritium and C14, which were
released through atmospheric atomic bomb test in the 1950s and 1960s,
entered the deep ocean in the northern Atlantic and are still moving
southward slowly. |
|
Those
pollutions just cross the equator in the Atlantic è They
have not reached the deep northern Pacific yet!! |
|
|
|
|
If the
warming is slow |
|
The
salinity is high enough to still
produce a thermohaline circulation |
|
The circulation will transfer the heat to deep
ocean |
|
The warming in the atmosphere will be deferred. |
|
|
|
If the
warming is fast |
|
Surface ocean becomes so warm (low water density) |
|
No more thermohalione circulation |
|
The rate of global warming in the atmosphere
will increase. |
|
|
|
|
|
|
|
Currents are in geostropic balance |
|
Each gyre includes 4 current components: |
|
two
boundary currents: western and eastern |
|
two
transverse currents: easteward and westward |
|
Western boundary current (jet stream of ocean) |
|
the fast, deep, and narrow current moves warm water polarward (transport ~50 Sv or greater) |
|
Eastern boundary current |
|
the
slow, shallow, and broad current moves cold water equatorward (transport ~
10-15 Sv) |
|
Trade wind-driven current |
|
the moderately shallow and broad westward current (transport ~ 30
Sv) |
|
Westerly-driven current |
|
the wider and slower (than the trade wind-driven current) eastward
current |
|
|
|
|
Western Boundary Current |
|
Gulf
Stream (in the North Atlantic) |
|
Kuroshio Current (in the North Pacific) |
|
Brazil Current (in the South Atlantic) |
|
Eastern Australian Current (in the South Pacific) |
|
Agulhas Current (in the Indian Ocean) |
|
Eastern Boundary Current |
|
Canary
Current (in the North Atlantic) |
|
California Current (in the North Pacific) |
|
Benguela Current (in the South Atlantic) |
|
Peru Current (in the South Pacific) |
|
Western Australian Current (in the Indian Ocean) |
|
|
|
|
|
|
|
|