IMS W4 Physical Oceanography

Question 1

Patterns of temperature

Answer 1

• Warm at the equator
• Atlantic water is warmer in higher latitudes
• Does not go below -2
• Pacific cold tongue at Galapagos

Question 2

Patterns of salinity

Answer 2

• 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

Question 3

Density

Answer 3

Differs on salinity and temperature. NOT pressure.

Question 4

Stable stratified ocean

Answer 4

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.

Question 5

Mixing

Answer 5

Only happens at the surface due to wind and tides/breaking waves by the moon

Question 6

Convection

Answer 6

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)

Question 7

Vertical structures in the ocean

Answer 7

Thermocline: quickly decrease and keeps decreasing
Halocline: short, quick decrease andincreases and stabilizes
Pycnocline: slow steady increase (density)

Question 8

Meridional heat transport

Answer 8

Convection of air. Air warms up and needs to be replenished by other air. Creation of cells.

Question 9

Sandström problem

Answer 9

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.

Question 10

Horizontal circulation

Answer 10

Measured by drifters.
Gyres.
Eddies

Question 11

ENSO

Answer 11

El Nino Southern Oscillation.
Sea surface temperature change (el nino) and atmosphere pressure gradient change (oscillation)

Question 12

Bjerkness feedback

Answer 12

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)

Question 13

Climate change and Lay-man’s summary

Answer 13

Most energy into the water.
Water takes up CO2 –> buffering effect –> ocean acidification.

Question 14

Changes to the thermohaline circulation

Answer 14

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.

Question 15

The equations of motion

Answer 15

Convervation of salt
Conservation of energy
Conservation of mass
The equation of state (stable stratified)
The conservation of momentum and angular momentum

Question 16

Two rules of Coriolis force

Answer 16

1. Always perpendicular to velocity
2. Proportional to speed magnitude

Question 17

Ekman balance

Answer 17

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.

Question 18

Ekman transport

Answer 18

The vertical motion of the ocean due to the horizontal motion in the first 50 m due to the forces.

Question 19

Convergence of flow

Answer 19

Ekman pumpin and suction

Question 20

Geostrophic balance

Answer 20

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.

Question 21

Full transition matrix

Answer 21

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.

Question 22

Plastic budget

Answer 22

Plastics from different locations. Most plastic comes from own shoreline. Beach clean ups are even more effective then fishing plastic out of the ocean.

Question 23

Effectiveness beach clean ups (6)

Answer 23

1. Most mass of plastic is macro size (> 5cm)
2. Most marine plastic originates from land
3. Macro plastic stays in coastal zone for a while
4. Plastic on a beach can be resuspended into the ocean
5. Fragmentation to microplastic occurs on coastlines
6. Beach cleanups are good for your mental health

Question 24

3 velocity flows

Answer 24

• geostropic (eddies and gyres)
• ekman transport (wind in the first 50 m)
• ekman pumping (vertical)