Chapter 10 Wind: Global Systems Flashcards
what is general circulation of the atmosphere?
the average air flow
unequal heating of the Earth’s surface is the basic cause of general circulation
-warm air is transferred from the tropics to the poles
-cool air is transferred from the poles to the tropics
what is the Single Cell Model?
assume:
1. no tilt
2. no land
3. no rotation
the Hadley cell: warm air moves from tropics to poles, and cool air moves from poles to tropics
no CF, winds blow from poles to equator
what is the Three Cell Model?
assume:
1. no tilt
2. land
add rotation
Creates:
- 3 vertical circulation cells in each hemisphere (hadley, ferrell, polar)
- alternating belts of pressure starting with L at equator
- alternating belts of wind with NE just north of equator
where are horse latitudes, doldrums, and the ITCZ?
horse latitudes: 30 degrees
doldrums: 0 degrees
Intertropical convergence zone: where the northeast east and southeast tradewinds converge
in the three cell model, where is temperature rising and sinking?
rising at:
-equator
-60 degrees N and 60 degrees S
sinking at:
-30 degrees N and 30 degrees S
-90 degrees N and 90 degrees S
what cause the surface wind belts?
pressure gradient force, Coriolis force, and friction force
what are semi-permanent highs and lows
Northern Hemisphere vs. Southern Hemisphere
major features shift seasonally with the high sun
what are the general circulation and precipitation patterns?
rain where air rises (low pressure)
less rain where air sinks (high pressure)
what are jet streams?
found between cells, narrow bands of swiftly flowing air currents hundreds of miles long
-moves west to east in waves
what are the two major jet streams, where are they and how long are they?
subtropical jet stream: 30 degrees, ~43,000 ft
polar front jet stream: 60 degrees, ~33,000 ft
what are gyres?
circular pattern of ocean currents created when the ocean surface is dragged by wind
-cold current, flowing north to sound, on west side of continent
-warm current, flowing south to north, on east side of continent
what is an Ekman Spiral?
fanned out layers of water
formed from coriolis force and friction force
what is Ekman Transport?
the average over the depth of the spiral to the right of the surface winds
90 degrees to the right of wind in NH
what is upwelling?
the rising of cold water from below
deep water comes up to replace water blown away by wind
what is southern oscillation?
alternating atmospheric pressures over the equatorial pacific change atmospheric circulation
causes: El niño and La niña
