Mid term 2 Flashcards
Whats Air pressure
Weight of the atmosphere(Motion, size, and number of molecules in the air) Heating of the air lowers the pressure of the air
What does Pressure Do ?
ITS responsible for the initial movement of air and The closer spacing of isobars, the higher pressure gradiant= the stronger wind
Whats the Coriolis effect
Since the earth rotates The wind/ Air masses deflect to the right in the northern hemisphere, deflect to the left in the southern hemisphere, No deflection at the equator and max deflection at the poles.
What occurs at a Low pressure system
Cyclones form at the centre of low atmospheric pressure.
- Air spirals inward and upward
-Associated with cloudy and rainy weather
- makes warm moist air
what happens at high pressure systems
Anti cyclone: center of high atmospheric pressure
- Air spirals downward and outward
- Fair weather
- makes cold, dry air masses
Hadley cells
- The closest cell to the equator
- Warm surface=low pressure
- Lighter(less dense) ascending air
- Converging air holding a lot of moisture
Ferrel Cells
- Between 30-60 degrees latitude
-Air sinks at 30 and moves towards the poles - ## Produces the “westerlies” at the surface (because of coreilos
Polar cells
- cold and dry air
-Air descends as it reaches the poles because it becomes colder and denser
-Variable wind direction because of weak heating =polar easterlies
Jet streams(polar)
- Due to Ferrel and polar cells and the Coriolis force converging
-winds of different temperatures and densities meet
-stronger when there are larger differences
-weak in summer strong in winter
Jet stream(subtropical)
Air from equator is warm and moist
-Air from poles is cold and dry = subtropical jet stream s
-where the Hadley and Ferrel cells meet
- weaker than the polar jet stream
Isobars
Lines on a map drawn through all points having the same atmospheric pressure
Global Circulation
Since the earth is rotating the equator receives more heat then the poles
Whats the order of the cells
Hadley at the Equator passes through the Subtropical jet stream, then into the Ferrel cell, then passes through the polar jet stream into Polar cells and at the very top, it’s the polar vortex
General Atmospheric Circulation Summary
- Polar circulation(60 degrees-> 90 degrees): polar front and polar jet stream cold air moves south
- latitude circulation(30-60 degrees): westerlies, subtropical high, sub-tropical jet stream
- tropical circulation(0-30degrees):
Trade winds, equatorial, Hadley cells - jet streams: polar and subtropical jet separate circulation zones
Thermocline
- The transition between warmer, well-mixed surface water and cold, stratified deep water.
- Epipelagic zone: region with enough sunlight for algae to use photosynthesis
Primary ocean forces
- solar heating
- winds
- coriolis
- gravity
solar heating
Heating causes water expansion
- 8 cm higher at equator than at mid-latitudes
- creates a slope water flows down the slope
Winds +gravity+Coriolis
- water will pile up in the direction the wind is blowing
- creates a a mound with slope- gravity tries to pull downhill
- but Coriolis acts against this and causes deflection to the right in the North hemosphere and left the south hemisphere
- This creates mounds in the ocean that water circulates: gyres
Gyres
- these are large circular currents in all major ocean basins
- there are 5 primary gyres in our oceans and one in the artic