February 25th lecture Flashcards
(30 cards)
What are Gyers?
Closed circulation loops within the ocean
What are sub-tropical gyers?
Gyers which flow clockwise ( anti - cyclonic ) in the northen Hemisphere
What are Sub - Polar gyers?
Gyers that flow counter clockwise ( cyclonic ) in the northern hemisphere.
What is PGF?
Pressure Gradient Force
What way are sub-tropical gyers deflected by the Coriolis effect? What dose this lead to?
They are deflected towards the center, leading to the sea surface mounding up in the tropics.
What is the balancing for of sub-tropical gyers?
Pressure gradient force pointed outwards, balancing out the inward pointing force due to the Coriolis effect.
What is a geostrophic circulation that flows around a mounded surface?
A sub-tropical gyer
What do gyers act like?
Gyers act like flywheels, spinning at a near constant speed that represents the average wind input to the gyer
What allows a gyer to not be dissipated by turbulence?
The winds blow frequently enough and the gyre stores enough energy, that it continuously spins and its motion is not dissipated by turbulence
What is different about sub-polar and sub-tropical gyers?
they spin in opposite directions
What effect does the Coriolis effect have on sub-polar gyers?
It causes the the currents to be deflected outwards from the gyer center, thus the sea center is depressed in these gyers
What way does the pressure gradient point in a sub-Polar gyer?
The pressure gradient points inwards as a balancing force.
What happens when there is a variation of the Coriolis parameter with latitude? (west)
- 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
What happens when there is a variation of the Coriolis parameter with latitude? (east)
- 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.
What happens when a gyer center is offset to the west?
A Western boundary current is compressed next to the continent, leading to a steep sea slope
What does a compressed western boundary current lead to? ( two things)
- this drives the faster gepstrophic currents
- The pycnocline is also pushed down, meaning that the boundary current is also deeper ( beside being faster (
in the atmosphere, what is climate?
The large scale, long term patterns with the local variations of weather superimposed
What is local weather in the ocean?
In the ocean, the ‘local weather” consists of meandering fronts and swirling motions, called eddies.
What are eddies?
Meandering fronts and swirling motions
What makes ocean eddies different from Atmosphere eddies? ( four things)
- they are smaller
- They are more numerous
- They move slower
- They last longer
Can ocean eddies be detected by satellites?
Yes they can be detected by satellite.
How are gulf stream rings formed?
They are formed by the meandering of the current, if a meander is tight enough it will pinch off and become an ring.
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?
The rings will contain water that is warmer or colder than the surrounding waters, resulting in warm core and cold core rings
What direction do warm core rings spin?
they spin clockwise (anti-cyclonic)
