February 25th lecture

Question 1

What are Gyers?

Answer 1

Closed circulation loops within the ocean

Question 2

What are sub-tropical gyers?

Answer 2

Gyers which flow clockwise ( anti - cyclonic ) in the northen Hemisphere

Question 3

What are Sub - Polar gyers?

Answer 3

Gyers that flow counter clockwise ( cyclonic ) in the northern hemisphere.

Question 4

What is PGF?

Answer 4

Pressure Gradient Force

Question 5

What way are sub-tropical gyers deflected by the Coriolis effect? What dose this lead to?

Answer 5

They are deflected towards the center, leading to the sea surface mounding up in the tropics.

Question 6

What is the balancing for of sub-tropical gyers?

Answer 6

Pressure gradient force pointed outwards, balancing out the inward pointing force due to the Coriolis effect.

Question 7

What is a geostrophic circulation that flows around a mounded surface?

Answer 7

A sub-tropical gyer

Question 8

What do gyers act like?

Answer 8

Gyers act like flywheels, spinning at a near constant speed that represents the average wind input to the gyer

Question 9

What allows a gyer to not be dissipated by turbulence?

Answer 9

The winds blow
frequently enough and the
gyre stores enough energy,
that it continuously spins
and its motion is not
dissipated by turbulence

Question 10

What is different about sub-polar and sub-tropical gyers?

Answer 10

they spin in opposite directions

Question 11

What effect does the Coriolis effect have on sub-polar gyers?

Answer 11

It causes the the currents to be deflected outwards from the gyer center, thus the sea center is depressed in these gyers

Question 12

What way does the pressure gradient point in a sub-Polar gyer?

Answer 12

The pressure gradient points inwards as a balancing force.

Question 13

What happens when there is a variation of the Coriolis parameter with latitude? (west)

Answer 13

• It is a result of the increase in Coriolis parameter as one moves pole-ward.
• Water moving eastward is deflected more than water moving westward
• This results in westerly zones water being transported towards the gyer center over the entire ocean width

Question 14

What happens when there is a variation of the Coriolis parameter with latitude? (east)

Answer 14

• In easterly wind zones, there is little deflection and water can flow across to pile up on the west side of the ocean
• This causes the gyer center to be offset to the west.

Question 15

What happens when a gyer center is offset to the west?

Answer 15

A Western boundary current is compressed next to the continent, leading to a steep sea slope

Question 16

What does a compressed western boundary current lead to? ( two things)

Answer 16

• this drives the faster gepstrophic currents

- The pycnocline is also pushed down, meaning that the boundary current is also deeper ( beside being faster (

Question 17

in the atmosphere, what is climate?

Answer 17

The large scale, long term patterns with the local variations of weather superimposed

Question 18

What is local weather in the ocean?

Answer 18

In the ocean, the ‘local weather” consists of meandering fronts and swirling motions, called eddies.

Question 19

What are eddies?

Answer 19

Meandering fronts and swirling motions

Question 20

What makes ocean eddies different from Atmosphere eddies? ( four things)

Answer 20

• they are smaller
• They are more numerous
• They move slower
• They last longer

Question 21

Can ocean eddies be detected by satellites?

Answer 21

Yes they can be detected by satellite.

Question 22

How are gulf stream rings formed?

Answer 22

They are formed by the meandering of the current, if a meander is tight enough it will pinch off and become an ring.

Question 23

With the string fronts separating the cold water to the north from the warmer water to the south, what effect does it have on the formation and composition of the rings?

Answer 23

The rings will contain water that is warmer or colder than the surrounding waters, resulting in warm core and cold core rings

Question 24

What direction do warm core rings spin?

Answer 24

they spin clockwise (anti-cyclonic)

Question 25

What direction do cold core rings spin?

Answer 25

They spin counter clockwise (cyclonic0

Question 26

How large do warm and cold core rings get

Answer 26

Both can reach sizes of 100-300 km in diameter and can

reach from the surface to the seafloor`

Question 27

How fast is the current of a warm or cold core ring at their rims?

Answer 27

The rotating currents at their rims can reach speed of ~90cm/s

Question 28

What lasts longer, warm core or cold core rings?

Answer 28

Cold core rings last longer because they are not limited in area (such as for warm core rings, which are limited to move between the Gulf Stream and land)

Question 29

Why are eddies important in the ocean?

Answer 29

Eddies are important for
transporting heat, nutrients
and marine organisms around

Question 30

What are Mesoscale eddies?

Answer 30

eddies that are roughly 25-200 km in diameter, with a rotating speed at the rim of roughly 10cm/s