winds “always blow from high to low”. “ferrel’s law” and the “coriolis force / effect”...

Winds

“Always blow from High to Low”

“Ferrel’s 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

That explains it

In Canada, water flushes clockwise!

In Australia, water flushes counter - clockwise!

Coriollis Effect:Tendency for winds to deflect to the RIGHT in the NORTH

and to theLEFT in the SOUTH

you are Really Nice but

you are Lazy Students

Winds• Are named for the direction from which

they blow, not the direction they are going

North

West Wind

“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

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

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

Warm, moist air

Cool, dry air

“Down in the Doldrums”

• This is the calm, windless area around the equator

• Sailors would get caught in them, going nowhere…

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

Trade Winds or Tropical Easterlies

Northeasttrades

southeasttrades

Trade Winds• Discovered by Christopher Columbus

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

• 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

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)

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

Polar Easterlies

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

Polar northeasterlies

Polar southeasterlies

Remember, air flows from highs to lows

LOW

LOW

LOW

HIGH

HIGH

HIGH

HIGH

WHAT IT REALLY LOOKS

LIKE:

DRAW IT!

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.

Sea Breeze

Land Breeze

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.

• 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.