Download Unit 2 part 4 winds 2014

2.3 WINDS
 Understand the cause of wind and
how they affect climate
 Chapter 4
 Pages 59-67
2.3.1
Know that air blows from
areas of high pressure to areas
of low pressure.
 The statement is fact.
 Think:
1. Air inside a balloon
2. Exhaling
3. Air powered pellet gun
4. It is simply fact.
 High and low pressures in the earth’s
atmosphere are responsible for wind
 P. 59-61
2.3.3
Define the terms wind &
prevailing wind. p.61-63
Wind = * flow of air.
* It results from air masses of different
temperatures and humilities lying next to each other
* The resulting pressure variation causes “wind” to
blow from high pressure area to low pressure area.
Prevailing Wind =
 Regular, predictable, normal
wind direction.
 Caused by global convection
cells
2.3.2
Application
 Using your knowledge of wind predict &
explain the wind directions below. P. 61
Sea Breeze
•Land air warmer than sea air
•Air rises over land
•Relative Low pressure over land
•Sea air moves to lower pressure
Land Breeze
•Sea air warmer than land air
•Air rises over sea
•Relative Low pressure over sea
•Land air moves to lower pressure
2.4.3
Describe how the coriolis force
affects wind direction.
Coriolis force =
 objects in motion tend to deflect
 to the right in north hemisphere
 to the left in south hemisphere
Consequently winds:
 in the northern hemisphere tend
to curve to the right
 while in the southern
hemisphere they deflect left.
*2.4.4
Make inferences about how winds are
related to major pressure belts. p.63
 Air rising from the equator
 Low pressures result
where hot air rises.
 High pressures
 Result = 6 convection cells
result where air
 3 above and 3 below the equator.
settles
 settles at the poles
2.4.2 –2.4.4 Summary of prevailing wind.
Sketch This
Write this
L
H
H
•global highs and lows
due to uneven heating of
the earth
•Air moves from high
pressure to low pressure
creating winds
L
H
•Winds are deflected in
the directions indicated
on the diagram due to the
coriolis effect.
L
H
2.4.5 Describe Orographic rainfall p. 66
Shinook







Moisture laden air blows off the sea
It is forced up by mountains (high relief)
Air cools at higher altitude
Cool air holds less moisture
Consequently clouds condense and rain falls
Most rain falls on the windward side of the relief
Leeward side is often in a dry rain shadow
because the moisture has all been lost
2.4.6 Describe Frontal rainfall p. 66
•Weather Front
•Hence the
name frontal
rain
 Warm Moisture laden air meets cold air
 Warm air is less dense & is forced up over the
cooler, more dense air
 Warm Moisture laden air cools at higher altitude
 Cool air holds less moisture
 Consequently clouds condense and rain falls
2.4.7 Describe Convectional rainfall p. 67
•Often
associated with
thunder storms.
 Usually occurs in hot areas like tropics or continental summer
 Sun heats the earth causing large amounts of water to




evaporate
Hot air rises forming convection currents (hence the name)
Warm Moisture laden air cools at higher altitude
Cool air holds less moisture
Consequently clouds condense and rain falls
2.4.8 Analyze the relationship between
wind systems and temperature.
 How do the
1.
2.
3.
4.
prevailing winds
affect temperature in:
Argentina
Columbia
Baffin Island
Newfoundland
2.4.9 Analyze the relationship between
wind systems and precipitation
 How do the prevailing
1.
2.
3.
4.
5.

winds affect
precipitation in:
England
Midwestern U.S.
British Columbia
Northern Africa
Central Australia
Question #26 p. 67 =
great active learning
lab