Chapter 7 Flashcards
1
Q
Circulation size is directly related to…
A
Lifetime
2
Q
Microscale Circulation
A
- lasts a few minutes
- Diameter 1 n.m. or less
e. g. Dust devils, Tornado’s, Thermals
3
Q
Mesoscale Circulations
A
- lasts 1 hr - 1 day
- Diameter “a few - several hundred kilometers”(slides)
- t-storms, down bursts, squall lines, land/sea breeze
4
Q
Macroscale Circulations
A
- lasts weeks - months - up to 1 year
- diameter 1,000 n.m. +
- jet streams, general circulation, monsoon circulation
5
Q
Global winds are?
A
Earths largest scale circulations
6
Q
Global winds are affected by?
A
- Equator/pole temp gradients
- Earths rotation
- Location of continents
- Seasonal changes
7
Q
General Circulation
A
- Ideal model of global winds
- Macroscale ~ 10,000 n.m.
- 1 full year to cycle
- can be divided according to factors affecting movement
- breaks down into cells
8
Q
Circulation cells
A
- 2 groups - 1 per hemisphere
- Temps at poles and equator create pressure gradients
- high pressure at poles
- low pressure at equator
- sets up thermal circulation
9
Q
North and South poles have high or low pressure? Why?
A
High - It’s cold and condenses the air
10
Q
Equator has high or low pressure? Why?
A
Low - It’s hot and expands the air
11
Q
Atmospheric circulations are mainly caused by?
A
Unequal heating of air
12
Q
Warm equatorial air…
A
Rises and expands
13
Q
When Equatorial air reaches the tropopause, what happens?
A
The air spreads out and moves towards the colder, polar regions
14
Q
Hadley Cell
A
- Strongest of the 3 cells
- air rises at equator, diverges at tropopause, deflected right (NH) -becoming upper-level westerly
- ~ 30° N Latitude air sinks and diverges at surface. Creating a semi-permanent high pressure system
- Called “Northeast Trade winds”
15
Q
What are the northeast trade winds?
A
- Part of hadley Cell
- ~ 30° north latitude
