1 / 17

Heat Transfer & Winds

Heat Transfer & Winds. Convection Currents in the Troposphere:. Heat from the Sun is the driving force behind these convection currents The Sun heats the Earth – air on surface to warms up Warm air rises

minh
Download Presentation

Heat Transfer & 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. Heat Transfer & Winds

  2. Convection Currents in the Troposphere: • Heat from the Sun is the driving force behind these convection currents • The Sun heats the Earth – air on surface to warms up • Warm air rises • As the air rises, it cools - density to increase and it will eventually sink back towards the Earth’s surface.

  3. Why are convection currents in the atmosphere so important? • As warm air rises it begins to cool which allows the water vapor in the air to condense into clouds • Without clouds there would be no precipitation

  4. What causes wind? • All winds are caused by differences in air pressure • These differences in air pressure are often caused by unequal heating of the atmosphere • Remember: • Air warms = expands • Cold air = contracts • Important note: • Do not worry about the exact temperature of the air. • Cooler air = high pressure • Warmer air = low pressure.

  5. Atmospheric Pressure: • ‘Weight of the atmosphere’ • Measured using a barometer • Can be expressed in either inches of mercury or millibars (mb)

  6. Pressure Gradient Force: • Air will always move from an area of high pressure to an area of low pressure

  7. Cyclones: • Center of low pressure where air converges • In the northern hemisphere cyclones spin counterclockwise L

  8. Anticyclones: • Center of high pressure where air diverges • In the northern hemisphere anticyclones spin clockwise H

  9. Weather Associated with a Cyclone: • The air is converging at a center of low pressure which will cause the air to rise • As the air rises it will cool and may condense into clouds • When a cyclone (low pressure) = potential for precipitation and foul weather

  10. Weather Associated with an Anticyclone: • The air is diverging at a center of a high pressure which will cause the air to sink • Sinking air = stabilizes the atmosphere in that area = prevents the formation of clouds • When an anticyclone (high pressure) = brings clear skies and no precipitation

  11. Local Winds: • Are named after where they come from • Do not effect a very large area • Santa Ana Winds in Southern California- • Hot, dry air comes down from the mountains • Temperature of the are can reach 100°F • Contributes to wildfires in the area

  12. Local Winds: sea breeze • During the day - land heats up more quickly than the water • High pressure over the water • Low pressure over the land • Since air moves from high pressure to low pressure, the wind will blow from the water to the land L H

  13. Local Winds: land breeze • After the sun sets - land will lose heat faster than the water • This results in high pressure over the land and low pressure over the water • Since air moves from high pressure to low pressure the wind will blow from the land to the water H L

  14. Global Wind Belts: calm areas • Doldrums- • Around the equator = area of low pressure • Even though the air rises very quickly there is very little horizontal movement and therefore very little wind.

  15. Global Wind Belts: trade winds • High pressure -> low pressure near the equator. • Winds generally blow from the northeast in the northern hemisphere and the southeast in the southern hemisphere • These are some of the most consistent and predictable winds on Earth

  16. Global Wind Belts: (continued) • Prevailing Westerlies- • Comes from the west -> east • Polar Easterlies- • Comes from the east -> west • Polar Front- • Where the polar easterlies and the westerlies meet up • In this location the mixing of warm and cold air has a major effect on weather changes in the US

  17. Jet Streams: • Bands of high speed winds about 10km above the Earth’s surface • The bands are very wide • Blow from west to east at speeds of 200-400 km/hr • As they travel around the Earth they wander along a wavy path

More Related