1. Chapter 19 The Atmosphere in Motion  Page 412  What special gear is the hang glider wearing?  What force is keeping the hang glider aloft?  What other kind of activities depend on this force?  What causes winds?

2. Chapter 19.1

3. Air Pressure and the Wind

4. What is air pressure? AAAA column of air that reaches from sea level to the tom of the atmosphere pushes down at 147lbs per square inch AAAAir pressure – is the weight of the overlying atmosphere IIIIt is exerted in all directions FFFForce pushing on your body is balanced by your body pushing out

5. TTTT hhhh eeee h h h h iiii gggg hhhh eeee rrrr y y y y oooo uuuu g g g g oooo i i i i nnnn tttt oooo t t t t hhhh eeee a a a a tttt mmmm oooo ssss pppp hhhh eeee rrrr eeee t t t t hhhh eeee l l l l oooo vvvv eeee rrrr tttt hhhh eeee p p p p rrrr eeee ssss ssss uuuu rrrr eeee BBBBarometers – used to measure air pressure –A–A–A–Aneroid – evacuated can with read outs attached and barograph –M–M–M–Mercury p 414 UUUUnits of air pressure –i–i–i–inches or millimeters – used to read mercury –m–m–m–millibars used on weather maps – these are adjusted to sea level pressure due to altitude differences

6. Why does air pressure Change Why does air pressure Change EEEElevation – higher up less air pressure TTTTemperature – the warmer (more spread out) the less Air P. WWWWater Vapor – the more water vapor the lower the A.P. – H2O molecules weigh less than the N & O molecules in the air IIIIsobars – lines of equal pressure – closed isobar forms a closed lop on a map

7. IIIIf pressure increases toward center it is a High Pressure Center LLLLow pressure center – pressure is lower PPPPressure Gradient – how close the isobars are. Close together – large gradient

8. What makes the wind blow DDDDifference in A.P. – the greater the difference the faster the winds. The closer the isobars the faster the wind AAAA wind blows form High P. to low P. –e–e–e–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 sea breeze

9. Measuring surface wind direction and speed. WWWWind vane – measure the direction from which the wind is blowing – Winds are named by the direction they come from –e–e–e–e.g. westerly or sea breeze AAAAnemometer – measure wind speed

10. Chapter 19.2

11. Factors affecting Wind

12. Coriolis Effect IIIIf the earth did not spin and was perfectly smooth air would flow strait from high pressure areas (poles) directly to low pressure areas (equator) CCCCoriolis effect causes objects traveling freely over the earth to curve –I–I–I–I nnnn n n n n.... h h h h eeee mmmm iiii ssss pppp hhhh eeee rrrr eeee c c c c uuuu rrrr vvvv eeee r r r r iiii gggg hhhh tttt –I–I–I–I nnnn s s s s.... h h h h eeee mmmm iiii ssss pppp hhhh eeee rrrr eeee c c c c uuuu rrrr vvvv eeee l l l l eeee ffff tttt –T–T–T–The effect is greater near the poles –T–T–T–The effect is also greater in long diastase travel vs. short travel –T–T–T–The effect increases with increased speed

13. FFFFriction – with the earth’s surface slows winds down. The smooth surface(water) the faster wind can blow the higher coriolis effect TTTThe coriolis effect is a strong factor in determining wind direction as is a Pressure gradient speed CCCC oooo rrrr iiii oooo llll iiii ssss c c c c aaaa uuuu ssss eeee ssss w w w w iiii nnnn dddd ssss t t t t oooo b b b b llll oooo wwww c c c c oooo uuuu nnnn tttt eeee rrrr cccc llll oooo cccc kkkk wwww iiii ssss eeee i i i i nnnn a a a a l l l l oooo wwww,,,, c c c c llll oooo cccc kkkk wwww iiii ssss eeee i i i i nnnn h h h h iiii gggg hhhh JJJJet stream – swift winds due to low friction – direct path of storms

14. Global Wind Patterns NNNNon rotating earth would allow warm air to rise at the equator, move to the poles and sink to travel back to the equator, resulting in large circulation cell TTTThe coriolis effect (Rotation of earth) prevents this from happening 3333 cell circulation model WWWWeakness of 3Celled model –g–g–g–gives simplified view of circulation between 30 and 60 –N–N–N–No effect given to continents or season –S–S–S–Simplifies upper level winds

15. B. Description of Wind and Pressure Belts IIIITCZ (intertropical convergence zone) occurs at the equator –h–h–h–hot and humid with little or no wind –r–r–r–rain is common –h–h–h–historically been called the doldrums BBBBetween 20 and 35 air sinks forming subtropical highs, location of earth’s deserts. Known as horse latitudes BBBBetween the doldrums and the horse latitudes are the easterly trade winds –W–W–W–Warm and steady (speed and direction) winds

16. Chapter 19.3

17. Continental and Local Winds

18. Effects of Seasons and continents SSSSeasons, land masses and topography causes winds to vary from global patterns depicted in the 3 cell model HHHHot air above land in summer creates low- pressure. Cold air above oceans in summer creates high pressure –e–e–e–e.g. Atlantic Highs bring winds off the ocean into the eastern sea board. Winter is reversed MMMMonsoons – winds caused by seasonal pressure changes

19. Local winds – extent 100 km or less include sea breeze, land breeze, mountain breeze and valley breeze SSSS eeee aaaa – – – – l l l l aaaa nnnn dddd b b b b rrrr eeee eeee zzzz eeee - - D D D D uuuu rrrr iiii nnnn gggg d d d d aaaa yyyy l l l l aaaa nnnn dddd i i i i ssss wwww aaaa rrrr mmmm eeee rrrr c c c c rrrr eeee aaaa tttt iiii nnnn gggg l l l l oooo wwww p p p p rrrr eeee ssss ssss uuuu rrrr eeee a a a a bbbb oooo vvvv eeee ```` cccc aaaa uuuu ssss eeee ssss t t t t hhhh eeee c c c c oooo oooo llll a a a a iiii rrrr ( ( ( ( HHHH )))) t t t t oooo b b b b llll oooo wwww iiii nnnn gggg f f f f rrrr oooo mmmm tttt hhhh eeee w w w w aaaa tttt eeee rrrr ( ( ( ( ssss eeee aaaa )))) a a a a nnnn dddd n n n n iiii gggg hhhh tttt i i i i tttt r r r r eeee vvvv eeee rrrr ssss eeee MMMMountain Breeze – at night the air against the mountain cools more than the surround air and sinks down hill VVVValley breeze – mountain heats the air causing it to rise and the air from the valley flows up hill