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Winds. Energy From the Sun. The atmosphere is the mixture of gases that surrounds the Earth. It is divided into 4 layers classified by temperature. Energy in the Atmosphere. energy in Earth’s atmosphere comes from the sun energy travels as electromagnetic waves
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Winds Energy From the Sun
The atmosphere is the mixture of gases that surrounds the Earth. It is divided into 4 layers classified by temperature.
Energy in the Atmosphere • energy in Earth’s atmosphere comes from the sun • energy travels as electromagnetic waves • Most of the energy is in the form of visible light and infrared radiation • A small amount of ultraviolet radiation
Electromagnetic Energy • Different forms of electromagnetic energy have different wavelengths. • Examples of electromagnetic energy are: • microwaves • infrared light • visible light • ultraviolet light • X-rays • gamma rays.
Visible light • Mixture of colors (ROYGBIV) • Different colors result of different wavelengths
Infrared Radiation • Wavelengths LONGER than red light • Not visible • Felt as heat
Ultraviolet radiation • Wavelengths that are SHORTER than violet light • Not visible • Causes sunburns, eye damage, skin cancer • Ozone in the stratosphere blocks most of the UV radiation
Heating of the atmosphere • Some of the energy is reflected/absorbed in the atmosphere • The rest is reflected/absorbed by the surface. • The greenhouse effect is a natural process by which gases hold heat in the air warming our planet.
Heat Energy • Thermal energy is the total energy of motion in the molecules of a substance. • “Heat" is used when energy is transferred from one substance to another.
Heat Energy Moves Heat moves from warmer objects to cooler ones until they reach the same temperature.
Heat Energy Moves • Heat can be transferred through: • Transfer of heat by direct contact (conduction) • Transfer by electromagnetic waves (radiation.) • In a liquid or gas, currents will cause the transfer of heat (convection.)
Heat Moves Through the Atmosphere • Convection causes most of the heating of the troposphere. • The upward movement of warm air and the downward movement of cool air form convection currents. • These currents cause wind.
What is wind? • Warm air expands and rises creating low pressure. • Cold air sinks and creates high pressure. • Winds are caused by differences in air pressure. • Winds move from high to low pressure.
Summary • Heating of Earth’s surface and atmosphere by the Sun drives convection within the atmosphere producing winds.
Local winds • winds that blow over short distances • Sea and land breezes • Unequal heating results in differences in pressures causing winds to blow
Global winds • Winds that blow steadily from specific directions over long distances • Temperature differences between the equator and the poles creates giant convection currents
Coriolis Effect • Global winds do NOT blow in a straight line • The Earth’s rotation causes the global winds to curve
Major Global Wind Belts • Trade winds • Prevailing westerlies • Polar easterlies
Horse Latitudes and Doldrums • Areas of little to no wind
Animation of global wind belts • http://vortex.weather.brockport.edu/~sweinbec/class/04_GlobalWind.swf