Chapter 19 The Atmosphere in Motion
I Air pressure and the wind
A. What is air pressure?
1. A column of air that reaches from sea level to the
tom of the atmosphere pushes down at _______ per
square inch
2. Air pressure – is the ____________of the overlying
atmosphere
3. It is exerted in _________directions
4. Force pushing on your body is balanced by your
body _______________out
5. The higher you go into the atmosphere the
_______________ the pressure
6. Barometers – used to measure air ________
Aneroid – __________ can with read outs attached
and barograph
a. Mercury p 414
7. Units of air pressure
a. inches or millimeters – used to read _______
b. _______________bars used on weather maps –
these are adjusted to sea level pressure due to
altitude differences
B. Why does air pressure Change
1. Elevation – higher up _____air pressure
2. Temperature – the __________(more spread out) the
less Air P.
3. Water Vapor – the more water vapor the
__________the A.P. – H2O molecules weigh less
than the N & O molecules in the air
4. ___________– lines of equal pressure – closed
isobar forms a closed lop on a map
5. If pressure increases toward center it is a
_____Pressure Center
6. Low pressure center – pressure is_________
7. Pressure Gradient – how ________the isobars are.
Close together – large gradient
C. What makes the wind blow
1. Difference in A.P. – the greater the difference the
faster the winds. The ________the __________the
faster the wind
2. A wind blows form___________. to low _______
e.g. Hot air on an island rises (form L.P.) Cool
air from the water (H.P) rushes in, this is
known as a ____________________
D. Measuring surface wind direction and speed.
1. ______________– measure the direction from which
the wind is blowing – Winds are named by the
direction they come ____________
e.g. westerly or sea breeze
2. Anemometer – measure _________________
II Factors affecting Wind
1. _______________Effect
1. If the earth did not spin and was perfectly smooth
air would flow strait from _________pressure
areas(poles) directly to ___________pressure
areas(equator)
2. Coriolis effect causes objects traveling freely over
the earth to curve
a. In n. hemisphere curve ________
b. In s. hemisphere curve ________
c. The effect is greater near the ______
d. The effect is also greater in _________
diastase travel vs. short travel
e. The effect increases with increased _________
3. Friction – with the earth’s surface slows winds
down. The __________ surface(water) the faster
wind can blow the ______________ coriolis effect
4. The coriolis effect is a strong factor in
determining wind direction as is a ___________
gradient speed
5. Coriolis causes winds to blow _______________ in
a low, clockwise in high
6. Jet stream – swift winds due to _______________ –
direct path of storms
III Global Wind Patterns
1. Non rotating earth would allow warm air to ________
at the equator, move to the poles and _________ to
travel back to the equator, resulting in large circulation
cell
2. The corriolis effect (_____________ of earth) prevents
this from happening
3. 3 ______________ circulation model
4. Weakness of 3Celled model
a. gives simplified view of circulation between
_______ and ____________
b. No effect given to continents or season
c. Simplifies upper level winds
B. Description of Wind and Pressure Belts
1. ITCZ (__________________ ________________
_______________) occurs at the equator
a. ___________and humid with little or no wind
b. ___________ is common
c. historically been called the ____________P_
2. between 20 and 35 air sinks forming
____________ highs, location of earth’s deserts.
Known as ______________________________
3. between the doldrums and the horse latitudes are
the easterly __________________
a. Warm and ___________ (speed and direction)
winds
IV Continental and Local Winds
A. effects of Seasons and continents
1. Seasons, land masses and topography causes
_________to vary from global patterns depicted in
the 3cell model
2. Hot air above land is summer creates _______pressure cold air. Above oceans in summer creates
high pressure
e.g. ____________ Highs bring winds off the
ocean into the eastern sea board. Winter is
reversed
3. ____________ – winds caused by seasonal pressure
changes
B. Local winds – extent 100 km or less include _______
breeze, lond breeze, mountain breeze and valley breeze
1. Sea – land breeze - During day land is warmer
creating low pressure above` causes the ______
air(H) to blowing from the water (sea) and night
it reverse
2. Mnt. Breeze – at night the air against the
mountain cools more than the surround air and
___________ down hill
3. ______________ breeze – mountain heats the air
causing it to rise and the air from the valley flows
up hill