Do Now05.19.10

What causes the seasons?

Objective State the reasons for global wind

patterns and ocean currents.

Coriolis effect: deflection of wind and ocean currents caused by the Earth’s rotation

Winds in N. Hemisphere flow to the right

Winds in S. Hemisphere

flow to the left

jet stream: narrow belt of strong, high speed air•height about 10 to 15 km above N. and S. Hemispheres

•closely related to weather

(2) global winds

http://www.weatherimages.com/data/imag192.html (current position)

anemometer: instrument that measures wind speed

wind vane: measures wind direction

*always points into the wind

wind

This is an easterly wind because it is blowing from the east

Doldrums

Uneven heating of air

Coriolis Effect

Ocean Currents Currents are the steady movement of

water in the ocean

Ocean Currents Currents are the steady movement of

water in the ocean• surface currents move on or near the

surface

Ocean Currents Currents are the steady movement of

water in the ocean• surface currents move on or near the

surface driven by the wind

Ocean Currents Currents are the steady movement of

water in the ocean• surface currents move on or near the

surface driven by the wind

• deep currents occur deep beneath the surface

Ocean Currents Currents are the steady movement of

water in the ocean• surface currents move on or near the

surface driven by the wind

• deep currents occur deep beneath the surface

caused by differences in the density of the water

Ocean Currents Currents are the steady movement of

water in the ocean• surface currents move on or near the

surface driven by the wind

• deep currents occur deep beneath the surface

caused by differences in the density of the water move very slowly

Surface Currents Wind provides energy to move large

masses of water

Surface Currents Wind provides energy to move large

masses of water upper layer of water moves the fastest

Surface Currents Wind provides energy to move large

masses of water upper layer of water moves the fastest

• velocity decreases with depth

Surface Currents Wind provides energy to move large

masses of water upper layer of water moves the fastest

• velocity decreases with depth• below 100m most surface currents are

undetectable

Surface Currents Surface currents are controlled by three

factors

Surface Currents Wind belts

Surface Currents Wind belts

• Trade Winds are located just north and south of the equator

Surface Currents Wind belts

• Trade Winds are located just north and south of the equator

push currents westward across tropical latitudes

Surface Currents Wind belts

• Trade Winds are located just north and south of the equator

push currents westward across tropical latitudes• Westerlies are located in the middle

latitudes

Surface Currents Wind belts

• Trade Winds are located just north and south of the equator

push currents westward across tropical latitudes• Westerlies are located in the middle

latitudes push eastward in the northern hemisphere

Surface Currents Wind belts

• Trade Winds are located just north and south of the equator

push currents westward across tropical latitudes• Westerlies are located in the middle

latitudes push eastward in the northern hemisphere in the south, pushes West Wind Drift completely

around the world

Surface Currents Wind belts

• Trade Winds are located just north and south of the equator

push currents westward across tropical latitudes• Westerlies are located in the middle

latitudes push eastward in the northern hemisphere in the south, pushes West Wind Drift completely

around the world• earth’s largest current

westerlies

Surface Currents Coriolis effect: deflection of the earth’s

winds and ocean currents

Surface Currents Coriolis effect: deflection of the earth’s

winds and ocean currents• caused by the rotation of the earth

Surface Currents Coriolis effect: deflection of the earth’s

winds and ocean currents• caused by the rotation of the earth

Gyres: huge circles of moving water

Surface Currents Coriolis effect: deflection of the earth’s

winds and ocean currents• caused by the rotation of the earth

Gyres: huge circles of moving water• caused by the combination of wind belts

and the coriolis effect

Surface Currents Coriolis effect: deflection of the earth’s

winds and ocean currents• caused by the rotation of the earth

Gyres: huge circles of moving water• caused by the combination of wind belts

and the coriolis effect• clockwise in the northern hemisphere

Surface Currents Coriolis effect: deflection of the earth’s

winds and ocean currents• caused by the rotation of the earth

Gyres: huge circles of moving water• caused by the combination of wind belts

and the coriolis effect• clockwise in the northern hemisphere• counterclockwise in the southern

Surface Currents Third factor affecting currents

Surface Currents Third factor affecting currents

• continents

Surface Currents Third factor affecting currents

• continents deflect and divide currents

Surface Currents Equatorial currents: westward moving

warm-water currents

Surface Currents Equatorial currents: westward moving

warm-water currents• Located in all three oceans

Surface Currents Equatorial currents: westward moving

warm-water currents• Located in all three oceans

currents in the northern hemisphere

Surface Currents Equatorial currents: westward moving

warm-water currents• Located in all three oceans

currents in the northern hemisphere• swift warm water moves north in the

western side of the oceans

Surface Currents Equatorial currents: westward moving

warm-water currents• Located in all three oceans

currents in the northern hemisphere• swift warm water moves north in the

western side of the oceans• Cool currents move south in the eastern

side

Surface Currents examples of warm water currents:

Surface Currents examples of warm water currents:

• Gulf stream

Surface Currents examples of warm water currents:

• Gulf stream• Japan current

Surface Currents examples of warm water currents:

• Gulf stream• Japan current• East Australia current

Surface Currents examples of warm water currents:

• Gulf stream• Japan current• East Australia current• Brazil current

Surface Currents examples of cool water currents:

Surface Currents examples of cool water currents:

• West Wind drift

Surface Currents examples of cool water currents:

• West Wind drift• California current

Surface Currents examples of cool water currents:

• West Wind drift• Californa current• Canary current

Surface Currents examples of cool water currents:

• West Wind drift• California current• Canary current• Peru current

Deep Currents move more slowly than surface currents

Deep Currents move more slowly than surface currents produced as cold, dense water sinks

below warmer water

Deep Currents move more slowly than surface currents produced as cold, dense water sinks

below warmer water• from cold polar regions towards the equator• denser because of higher salinity