1 / 23

WINDS

WINDS. Understand the cause of wind and how they affect climate Chapter 4 Pages 59-67. What is Wind?. A wind is a horizontal movement of air across a surface. Vertical movements are currents or updrafts and downdrafts Caused by what????

zaria
Télécharger la présentation

WINDS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. WINDS Understand the cause of wind and how they affect climate Chapter 4 Pages 59-67

  2. What is Wind? • A wind is a horizontal movement of air across a surface. • Vertical movements are currents or updrafts and downdrafts • Caused by what???? • Heat versus cold!! Relate it to convection cells previously studied!!!

  3. What causes wind? • Unequal heating • Unequal heating causes pressure differences • Cold, heavy air sinks = high pressure • Warm, expanding air rises = low pressure • Winds blow from high to low

  4. Know that air blows from areas of high pressure to areas of low pressure. • The statement is fact. • Think: • Air inside a balloon • Exhaling • Air powered pellet gun • It is simply fact. • High and low pressures in the earth’s atmosphere are responsible for wind • P. 59-61

  5. Application - Land Breeze • Using your knowledge of wind predict & explain the wind direction below. P. 61 • FACT: Water holds heat longer than the land. • During the night, sea air is warmer than the air over the land. • Air rises over sea • Relative Low pressure over sea • Land air moves to lower pressure Low Pressure

  6. Land Breeze • Night time • Cool breeze • Off the land

  7. Application - Sea Breeze • Using your knowledge of wind predict & explain the wind direction below. P. 61 • FACT: Land heats up faster than the water • During the day, air over the land is warmer than air over the sea • Air rises over land • Relative Low pressure over land • Sea air moves to lower pressure • Cold “Breeze” off the ocean during the day Low Pressure

  8. Sea Breeze • Day time • Cool Breeze • Off the ocean

  9. Define the terms wind & prevailing wind. p.61-63 Wind: • is a horizontal movement of air across a surface. • It results from air masses of different temperatures and humidity lying next to each other. • The resulting pressure variation causes “wind” to blow from high pressure areas to low pressure areas. Prevailing Wind: • Is regular, predictable, normal wind direction for a given area or region. • Caused by global convection cells. • Named after the direction from which it comes

  10. Prevailing Winds Lab

  11. Prevailing Winds

  12. Describe how the coriolis force affects wind direction. Coriolis force = • objects in motion tend to deflect • to the right in north hemisphere • to the left in south hemisphere Consequently winds: • in the northern hemisphere tend to curve to the right of their path. • while in the southern hemisphere they deflect left of their path.

  13. Summary of prevailing wind • Global highs and lows are due to uneven heating of the earth • Air moves from high pressure to low pressure creating winds • Winds are deflected in the directions indicated on the diagram due to the coriolis effect.

  14. Make inferences about how winds are related to major pressure belts. p.63 • Air rises at the equator • It settles at the poles • Result = 6 convection cells • 3 above and 3 below the equator. • Low pressures result where hot air rises. • High pressures result where air settles

  15. Describe Orographic rainfall p. 66 Leeward Chinook • A relatively warm, moist air blows off the sea • It is forced up by mountains (high relief) • Air cools at higher altitude • Cool air holds less moisture • Consequently clouds condense and rain falls • Most rain falls on the windward side of the relief • Leeward side is often in a dry rain shadow because the moisture has all been lost Windward

  16. Definitions • Windward • The side of the mountain receiving the wind • (consequently more precipitation as well) • Leeward • The side of the mountain sheltered from the wind • (consequently receives less precipitation) • Rain Shadow • The area located on the leeward side of a mountain that receives low amounts of precipitation. • Mainly due to the air that descends on the leeward side has “dumped” on the windward side.

  17. Describe Frontal rainfall p. 66 • Weather Front-2 fronts meet • Hence the name frontal rain • Warm Moisture laden air meets cold air • Warm air is less dense & is forced up over the cooler, more dense air • Warm Moisture laden air cools at higher altitude • Cool air holds less moisture • Consequently clouds condense and rain falls FRONT Warm, moist air

  18. Describe Convectional rainfall p. 67 • Often associated with thunder storms. • Usually occurs in hot areas like tropics or continental summer • Sun heats the earth causing large amounts of water to evaporate • Hot air rises forming convection currents (hence the name) • Warm Moisture laden air cools at higher altitude • Cool air holds less moisture • Consequently clouds condense and rain falls Air heated from the earth

  19. Analyze the relationship between wind systems and temperature. • How do the prevailing winds affect temperature in: • Argentina • Columbia • Baffin Island • Newfoundland

  20. C D B A

  21. Analyze the relationship between wind systems and precipitation • How do the prevailing winds affect precipitation in: • England • Midwestern U.S. • British Columbia • Northern Africa • Central Australia • Question #26 p. 67 = great active learning lab

  22. A C B D E

More Related