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Wind Formation. WHAT HEATS EARTH’S SURFACE?. Heat from the sun heats the surface of the Earth. This heat arrives to Earth in the form of radiation. Radiation is the transfer of energy by electromagnetic waves. CONVECTION. transfer of heat by the movement of warmed matter.
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WHAT HEATS EARTH’S SURFACE? • Heat from the sun heats the surface of the Earth. • This heat arrives to Earth in the form of radiation. • Radiation is the transfer of energy by electromagnetic waves.
CONVECTION transfer of heat by the movement of warmed matter
Atmospheric Density What is most dense SINKS!
CONVECTION Moves air in the atmosphere!
Convection Convection causes the rise and fall of air in the atmosphere… v
Wind Formation • Air is a fluid and can move from place to place. • Fluids move from areas of high pressure to low pressure. • Winds are caused by differences in air pressure.
Wind Formation • Air moves from areas of HIGH pressure to areas of LOW pressure. • This movement of the air is the wind Example: When you blow up a balloon, you increase the air pressure inside the balloon. When you let go of the end, the air rushes out of the balloon
Wind Formation • Let’s think about this: What factors are responsible for differences in air pressure? • Temperature and Density!!! • As air warms, it expands and becomes less dense. Lower density creates a lower air pressure.
What causes differences in air pressure? • Differences in air pressure are caused by UNEVEN HEATING of the Earth’s surface by the sun. • Therefore, the sun and solar energy is the ultimate cause of the wind.
Convection cells • Winds do not travel straight from the equator to poles. • Due to the cycling of high and low pressure- wind travels via convection cells. Convection cells are: • Pockets of cycling warm, less dense, low pressure air with cool, denser high-pressure air. • Pressure difference results in global movement of air.
Coriolis Effect • Because of the Earth's rotation, any freely moving object or fluid will appear to: • Turn to the rightof its direction of motion in the Northern Hemisphere and • Turn to the leftof its direction of motion in the Southern Hemisphere.
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