Winds

1
Winds

• Always blow from High to Low

2
If the earth stood still
3
But it rotates
4
Ferrels Law and the Coriolis Force / Effect

• Is a deflective force caused by the rotation of
  the earth on its axis

• All particles in motion are deflected toward the
  right in the Northern Hemisphere

• All particles in motion are deflected toward the
  left in the Southern Hemisphere

5
That explains it ?
In Australia, water flushes counter - clockwise!
In Canada, water flushes clockwise!
6
Coriolis EffectTendency for winds to deflect to
the RIGHT in the NORTH and to theLEFT in the
SOUTHyou are Really Nice but you are Lazy
Students
7
(No Transcript)
8
Winds

• Are named for the direction from which they blow,
  not the direction they are going

North
West Wind
9
Hadley Cell

• On or near the equator, where solar radiation is
  greatest, air is warmed at the surface and rises

• This creates a band of low air pressure, called
  the intertropical convergence zone (ITCZ)

• On or near the equator, where solar radiation is
  greatest (between 12oN and 8oS), air is warmed at
  the surface and rises

• The ITCZ draws in surface air from the subtropics

10

• This subtropical air rises into the upper
  atmosphere, then begins flowing horizontally to
  the North and South Poles

Warm, moist air
Cool, dry air

• The Hadley cell eventually returns air to the
  Earths surface near 30o North and South

11
Down in the Doldrums

• This is the calm, windless area around the equator

• Sailors would get caught in them, going nowhere

12
Trade Winds or Tropical Easterlies

• These winds are deflected from east to west as
  they travel toward the equator by the coriolis
  force

Northeast trades
southeast trades
13
Trade Winds

• Discovered by Christopher Columbus

• Smart sailors sought out the trades to go west
  (sailed fast)

14

• The other portion of that surface air moves
  towards the poles from the subtropical high zone

• This air, also deflected by the Coriolis Force,
  are called the Westerlies

Prevailing southwesterlies
Prevailing northwesterlies
15
The Westerlies

• These powered Columbus return trip to Europe

• They are also responsible for the better surfing
  found on the Pacific side of North America (blow
  in the same direction as the waves heading toward
  shore, building up their height)

16
Horse Latitudes

• This is another calm area found between the trade
  winds and the westerlies

• Caught in this calm for weeks, sailors could
  starve

• Horses, common cargo back then, would be thrown
  overboard to lighten the load ?

17
Polar Easterlies

• The high pressure of the Polar High forces air
  away towards the Polar Low

Polar northeasterlies
Polar southeasterlies
18
Remember, air flows from highs to lows ?
HIGH
LOW
HIGH
LOW
HIGH
LOW
HIGH
19
WHAT IT REALLY LOOKS LIKE
20
(No Transcript)
21
DRAW IT!
22
LAND AND SEA BREEZES

• During the day, the land heats up more rapidly
  than does the sea. Air rises over the land,
  creating a low-pressure area. Cooler air flows in
  to this area from the sea, creating a sea breeze.
• During the night, the land cools more rapidly
  than the sea, and the reverse flow, a land
  breeze, occurs.

23
(No Transcript)
24
Valley and Mountain Breezes

• Mountain Breeze Katabatic WindCool Air shoots
  down the sides of mountain down into the valley.
  In the summertime, this occurs at night.

25

• Valley Breeze Anabatic Wind. Warm air rises up
  the mountain sides, causing breeze which flows up
  the valley. During the summer, this occurs
  during the day.