Solar Energy and the Atmosphere Earth and Space Science Ms. Pollock 2009 - 2010
Radiation All forms of energy that travel through space as waves Speed 300,000 km/s Wavelength – distance from crest to crest or trough to trough Electromagnetic spectrum – complete range of wavelengths of electromagnetic waves
Electromagnetic Spectrum http://www.atmos.washington.edu/~hakim/301/electromagnetic-spectrum.jpg
The Atmosphere and Solar Radiation Upper atmosphere absorbs almost all radiation with wavelength shorter than visible light Molecules of N and O absorb X rays, gamma rays, UV rays In stratosphere, oxygen uses radiation to form ozone
The Atmosphere and Solar Radiation http://www.global-greenhouse-warming.com/images/SolarRadiationDiagram.jpg
The Atmosphere and Solar Radiation Most solar rays reaching lower atmosphere longer wavelengths Infrared radiation absorbed by CO2
Scattering http://images.google.com/imgres?imgurl=http://science.nayland.school.nz/hamishm/images/sunrise.jpg&imgrefurl=http://science.nayland.school.nz/hamishm/&usg=__P5fIW_2hfR9_QXr-jiwBhMJsA0c=&h=907&w=1238&sz=191&hl=en&start=2&tbnid=baaXk0iBCn-5yM:&tbnh=110&tbnw=150&prev=/images%3Fq%3Dsunrise%26gbv%3D2%26hl%3Den Particles and gas molecules in atmosphere reflect and bend solar rays Some radiation back to space Sunlight from all directions Blue sky and red sunrise and sunset
Reflection Earth’s surface absorbing or reflecting energy Physical properties of surface determine absorption or reflection albedo – fraction of solar radiation reflected by a surface http://www.energyeducation.tx.gov/environment/section_3/topics/predicting_change/img/albedo.gif
Absorption and Infrared Energy Not all radiation ever absorbed Heating of surface materials Reemission of radiation with altered wavelength Necessary for maintenance of temperature of lower atmosphere Causes mirage
Absorption and Infrared Energy http://www.astronomycafe.net/weird/lights/mirage6.jpg
The Greenhouse Effect Greenhouse glass allows light and infrared rays in. The glass also prevents the reflected rays from escaping the greenhouse. Earth’s atmosphere acts in the same way. http://andrian09.files.wordpress.com/2008/12/greenhouseeffectdiagram.jpg
Human Impact on the Greenhouse Effect http://www.myclimatechange.net/UserImage/3/Definition/GreenhouseEffect.jpg Generally, the amount of energy entering the atmosphere and the amount of energy leaving the atmosphere is equal. Human activities upset the balance Burning fossil fuels
Variations in Temperature Unequal heating of Earth Delay between radiation reaching Earth and temperature increasing Warmest time of day mid- to late afternoon Depends on latitude, surface features, season, and time of day
Latitude and Season Because of Earth’s shape, sun does not strike everywhere at same angle At equator, rays striking at near 90º More intense radiation Seasonal temperature variation because of Earth’s tilt on axis Opposite seasons in northern and southern hemisphere
Latitude and Season http://www.learner.org/jnorth/images/imageshtml/earth-tilt.gif
Water in the Air and on the Surface Water vapor stores heat. Wide temperature variation in very dry areas or areas with high altitudes Land areas near large bodies of water less variant, due to specific heat of water Temperature variations caused by wind patterns
Water in the Air and on the Surface http://www.free-online-private-pilot-ground-school.com/images/sea-land-breeze.gif
Conduction Transfer of energy from one substance to another by direct contact Results from particle collisions Air a poor conductor due to large spaces between particles Conduction only in lower portion of atmosphere
Conduction http://blogs.saschina.org/sophie01pd2016/files/2009/10/heat-transmittance-means.jpg
Convection Process by which a fluid rises or sinks because of a difference in temperature Result of uneven heating Primary source of heating in lower atmosphere Pressure difference between air of different temperatures creates wind.
Convection http://npg2.com/krdo/weatherblog/wordpress/wp-content/uploads/2008/08/convection_explainer.gif