Winds Energy From the Sun
The atmosphere is the mixture of gases that surrounds the Earth 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
Sea/lake and land breezes
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