Coastal Geography, Oceanography

Question 1

Mixed layer

Answer 1

The upper part of the ocean that is in contact with the atmopshere that plays an important role in wind mixing and heat exchange. It is roughly 50m deep and is affected by seasonal variation

Question 2

Which two main properties of the mixed layer are uniform

Answer 2

Temperature and salinity

Question 3

Ocean currents

Answer 3

Masses of ocean water that flow from one place to another due to wind setup.

Question 4

How does coriolis force influence ocean currents?

Answer 4

Currents deflect to the right in the Northern Hemisphere whilst deflecting to the left in the Southern Hemipshere

Question 5

What is the process of Ekman transport

Answer 5

Water is deflected either right or left depending on the hemisphere. This movement is passed through the ocean column so that the ‘average’ net transport of water is at right angles to the initial wind direction

Question 6

At what depth does Ekman transport occur

Answer 6

Shallow surface of the ocean: < 100m

Question 7

Upwelling

Answer 7

The movement of cold, nutrient-rich water from the depths of the ocean to the mixed layer

Question 8

Downwelling

Answer 8

The movement of warm, nutrient-poor water from the suface of the ocean to the coast

Question 9

What do Southward winds near the coast do?

Answer 9

Southward winds along the coast cause upwelling, thus producing cold temperatures near the coast

Question 10

What do Northward winds near the coast do?

Answer 10

Northward winds near the coast cause downwelling, thus producing warmer temperatures near the coast

Question 11

Why are waters near the Equator nutrient rich?

Answer 11

Due to Coriolis force, downwelling causes warm, nutrient-poor water to flow away from the Equator in both the Northern and Southern Hemisphere

Question 12

Subtropical gyre

Answer 12

Huge, circular surface currents cased by ocean currents being deflected right and left due to Coriolis force

Question 13

What does Ekman transport do in subtropical gyres?

Answer 13

Water is piled in these gyres, slightly eleavting the water over a vast area

Question 14

How do Western boundary currents influence subtropical gyres

Answer 14

In each subtropical gyre, Western boundary currents return warm water to the poles

Question 15

How is the Gulf Stream an example of a Western boundary current

Answer 15

Water in the subtropical gyres is returned in strong, narrow currents along the Western boundaries of the Gulf

Question 16

Why does the Antarctic circumpolar current keep warm water away from Antarctica?

Answer 16

The Antarctic circumpolar current is driven by strong Westerly winds that flow clockwise around the continent.

Question 17

Why is the Antarctic circumpolar current significant?

Answer 17

It conects all of the oceans (Pacific, Atlantic, and Indian), and allows them to exchnage currents

Question 18

What drives deep ocean circulation?

Answer 18

Deep ocean circulation is driven by differences in water densities

Question 19

Thermohaline circulation

Answer 19

A type of ocean circulation that is driven by differences in temperature and salinity within the oceans’ strata

Question 20

Why is thermohaline circulation important?

Answer 20

Thermohaline circulation is important because it brings oxygen to deep water (for plankton to perform photosynthesis) while also bringing nutrients to the surface. Additionally, it also regulates climate by driving warmer surface waters to the poles from the subtropics

Question 21

What are the two main ocean currents around New Zealand?

Answer 21

The return flow of the Western boundary current and the Antarctic circumpolar current

Question 22

Bathymetry

Answer 22

The seafloor (like topology for land)

Question 23

What are the names of the two shallow parts of land surrounding New Zealand?

Answer 23

The Kermadec Trench (North) and the Campbell Plateau (South)

Question 24

How does New Zealand’s bathymetry influence deep ocean currents?

Answer 24

The Western boundary current flows North along the Kermadec Trench while the Antarctic circumpolar current flows East along the Campbell Plateau