Chapter 3: Circulation of Air and Ocean Currents Flashcards
What is earths heat engine? What does it drive?
Radiation influx exceeds outflow near the equator. This heated air moves towards the poles due to the tilt of the earth. Heated air at equator rises and moisture is lost leading to precipitation, this heated air moves and cools by sinking at 30˙, these convection cells are called Hadley cells. The flow of this heat from equator moves towards the poles
Movement of this air drives air over water currents causing the movement of ocean currents, and the planetary winds are also controlled by this
What is the coriolis effect?
The movement of fluids in relation to earths rotation beneath results in deflections of the water
- Earths rotation
- Faster speed of objects at the earths equator
- This occurs by centrifugal and gravitational forces
What type of winds does this create and what directions do objects move in each hemisphere?
It creates Easterlies and Trade winds and creates anticyclonic patterns of local weather
Areas of low wind include doldrums, and horse latitudes
In the north hemisphere objects will move to the right and in the southern hemisphere objects will move to the left
What does the coriolis effect create? What does that do?
It creates Ekman transport which causes different sheets of the water column to shift left 90 degrees in the S.H and shift right 90 degrees in the N.H and will only effect the surface layer.
What are Gyres?
A combination of wind and the shape of ocean basins create cyclonic flow known as Gyres. Where the Gyres interact with landmasses will tend to concentrate boundary currents on either sides of the ocean
What are examples of Western and Eastern Gyres?
Western is Gulf Stream (moves warm water moving north) and Kroshio current
And Eastern is California current where cold water brought south
What does coriolis effect (Ekman transport) and continents create?
This will cause upwelling where deeper ocean waters and brought up to the surface
What is ENSO?
A 2-10 year climate cycle which results from unstable cross pacific currents or also know as oscillations.
What is La nina?
Warm waters move westward causing steep thermoclines off Peru and wet Indopacific, also known as normal conditions
What is El nino?
Warm waters slosh back eastward which reduces thermocline which ultimately reduces upwelling causing wet South America
What is NAO?
North Atlantic Oscillaition results from pressure differential across Atlantic between Iceland and Azores for southern Europe…
+ (strong low and high pressures) = normal, strong westerlies, mild wet winters, cool summers.
- (weaker low and high pressures) = weak westerlies, extreme weather freezing winters and hot summers
How does oceanic circulation occur?
Wind driven surface circulation due to coriolis effect, gyres, boundary currents, and upwellings
Also driven by density driven thermocline circulation
What is thermohaline circulation?
The movement of ocean water moved by density characteristics where masses can be divided into temperatures, salinity and other chemical characteristic, also known as the global conveyor belt
