4.5 STORMS Flashcards
What forces tropical/extra tropical storms (cyclones) to exist?
Energy from the sun
Rotation of the earth
at any one time there are multiple weather systems active around the globe with variable atmos pressures & winds. when these pressures and winds are averages over many years, a well-defined global circulation pattern appears.
How is the earth tilted in a northern hemisphere summer?
- north pole tilted towards the sun
- sun’s rays strike n. hem. more DIRECTLY in summer
- summer solstice = june 21 or 22; sun’s rays hit earth most directly along the tropic of cancer (23.5deg N)
How is the earth tilted in a northern hemisphere winter?
- tilt of the earth’s axis points away from the sun
- light from the sun is spread out over larger area, so it’s not heated as much
- fewer daylight hours => less time for sun to warm area
- winter solstice for northern hem = dec 21 or 22
What are the three hemisphere cells?
- hadley
- ferrel
- polar
What happens in the troposphere?
the part of the atmosphere where most of the weather takes place.
What are idealised pressure belts and resulting wind systems significantly modified by?
- EARTH’S TILT - which produces the seasons
- The air of the continents gets colder in the winter & warmer in the summer than the air over adjacent oceans because of the HEAT CAPACITY of water compared to rock
- As a result, during winter, continents usually develop HIGH PRESSURE CELLS; during summer, they develop LOW PRESSURE CELLS
What are cyclones like in the Northern hemisphere?
- air currents bend to the RIGHT
- so the cyclones rotate ANTICLOCKWISE
What are cyclones like in the Southern hemisphere?
- air currents bend to the LEFT
- this makes cyclones rotate CLOCKWISE
What are cyclones?
Large air masses that rotate around a center. As they rotate, they pull air into that center/eye.
What is the Coriolis effect on regular winds in the Northern hemisphere?
- As warm air rises near the equator, it flows towards the poles.
- In the N. hem., these warm air currents move to the RIGHT as they travel north
- they BEND EAST