IMS W4 Physical Oceanography Flashcards
Patterns of temperature
- Warm at the equator
- Atlantic water is warmer in higher latitudes
- Does not go below -2
- Pacific cold tongue at Galapagos
Patterns of salinity
- Atlantic is the most saline due to transpiration
- Subtropical areas are more saline then equator
- Artic is less saline than the Antarctic
- River flows affect the salinity
- Scale is much smaller than temperature
Density
Differs on salinity and temperature. NOT pressure.
Stable stratified ocean
A blob of water with a different density will oscillate: go down in lighter density area and up in higher density area. This can do on for weeks. Internal wave.
Mixing
Only happens at the surface due to wind and tides/breaking waves by the moon
Convection
Water does not oscillate but just keeps moving downwards. Happens at cool waters where fresh water is taken (forming ice). –> cold, very saline water (Brimm Rejection)
Vertical structures in the ocean
Thermocline: quickly decrease and keeps decreasing
Halocline: short, quick decrease andincreases and stabilizes
Pycnocline: slow steady increase (density)
Meridional heat transport
Convection of air. Air warms up and needs to be replenished by other air. Creation of cells.
Sandström problem
Mechanically driven heat engine. Ocean is not driven by convection such as the air. It is turned by mechanical energy input from wind and tides.
Horizontal circulation
Measured by drifters.
Gyres.
Eddies
ENSO
El Nino Southern Oscillation.
Sea surface temperature change (el nino) and atmosphere pressure gradient change (oscillation)
Bjerkness feedback
Easterly trades drive divergence and upwelling in the east –> warm water to the west –> thermocline in the east decomes shallow and deep in the west –> large SST (Nino Index Regions) differences (Walker circulation)
Climate change and Lay-man’s summary
Most energy into the water.
Water takes up CO2 –> buffering effect –> ocean acidification.
Changes to the thermohaline circulation
AMOC (Atlantic Meridional Ocean Ciculation) is weakened. Less warm water to the poles. Less heat energy to the northern latitudes. Less cooling of the water at the poles causing it not to sink.
The equations of motion
Convervation of salt
Conservation of energy
Conservation of mass
The equation of state (stable stratified)
The conservation of momentum and angular momentum
Two rules of Coriolis force
- Always perpendicular to velocity
- Proportional to speed magnitude
Ekman balance
Due to wind force and the Coriolis force the velocity is on the left from the force on the southern hemispheren and the right on the northern.
Ekman transport
The vertical motion of the ocean due to the horizontal motion in the first 50 m due to the forces.
Convergence of flow
Ekman pumpin and suction
Geostrophic balance
The pressure gradient on the hills of eddies create a different force on the velocity of water. Moves all water around but does not accumulate things at the center of gyres.
Full transition matrix
Creation of a model to measure the garbage patches in the ocean. Made with drifters and the chance they move into a certain grid in a period of time.
Plastic budget
Plastics from different locations. Most plastic comes from own shoreline. Beach clean ups are even more effective then fishing plastic out of the ocean.
Effectiveness beach clean ups (6)
- Most mass of plastic is macro size (> 5cm)
- Most marine plastic originates from land
- Macro plastic stays in coastal zone for a while
- Plastic on a beach can be resuspended into the ocean
- Fragmentation to microplastic occurs on coastlines
- Beach cleanups are good for your mental health
3 velocity flows
- geostropic (eddies and gyres)
- ekman transport (wind in the first 50 m)
- ekman pumping (vertical)
