1.4 - Variations in Wind Direction and Speed across the Earth's Surface Flashcards
1
Q
Pressure Gradient
A
Difference in air pressure between 2 locations
2
Q
High and Low Pressure Causes
A
- Pressure varies with temperature
- Warm air expands, becomes less dense, rises = low pressure
- Cool air contracts, becomes denser, sinks = higher pressure
3
Q
What are Winds?
A
Horizontal movement of air across Earth’s surface from an area of high to low pressure
4
Q
How are Winds formed?
A
- Difference in pressure forms pressure gradient
- Air moves from area of high to low pressure to fill in the void. Winds formed.
5
Q
What determines Wind Speed?
A
- The greater the pressure gradient, the faster the wind speed
- Variations in Earth’s topography -> frictional drag -> reduced wind speed
- Uneven relief and rough surfaces on land -> greater frictional drag ->greater reduction in wind speed
6
Q
Local Winds
A
Land Breeze and Sea Breeze
- Lower day temp, regulate night temp
- Result in smaller diurnal temp range
7
Q
Land Breeze
A
- Occurs at Night
- 1) Wind that blows from land to sea
2) At night, land cools faster than sea, cool air sinks over land
3) Air pressure over land is higher than the sea
4) Air moves from an area of high pressure to area of lower pressure, wind blows from land to sea.
8
Q
Sea Breeze
A
1) Breeze that blows from sea to land
2) During the day, land heats up faster than the sea, resulting an a region of higher pressure over the sea
3) Since air moves from a region of higher pressure to a region of lower pressure, wind blows from the sea to the land.
9
Q
Coriolis effect
A
NH: deflects right
SH: deflects left
10
Q
Regional Winds
A
- Northeast Monsoon
- Southwest Monsoon
11
Q
Northeast Monsoon
A
October to February
- Summer in Australia (S), Winter in Central Asia (N)
12
Q
Southwest Monsoon
A
June to September
-Summer in Central Asia (N), winter in Australia (S)
