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Air B. Radiation and Climate. Solar Radiation. The sun (Sol) is a huge fusion reactor - combines two nuclei of H to a He atom. The produces a tremendous amount of energy Stars are the “birthplace” of all elements in the universe through the process of fusion. Solar Radiation.
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Air B Radiation and Climate
Solar Radiation • The sun (Sol) is a huge fusion reactor - combines two nuclei of H to a He atom. • The produces a tremendous amount of energy • Stars are the “birthplace” of all elements in the universe through the process of fusion.
Solar Radiation • Some of the energy from the sun is in the form of electromagnetic radiation - low to high types of energy. • All electromagnetic radiation is part of the electromagnetic spectrum
Electromagnetic Radiation • Electromagnetic Radiation is composed of photons • Photons are small bundles of energy • Photons travel as waves - at the speed of light • Photons can travel through a vacuum - they don’t need a medium to travel on (like sound)
Properties of Waves • Frequency - how many times a waves passes per amount of time. • Wavelength - the distance between two adjacent waves. • Must be the same “part” of the wave. • The wavelength and frequency along with the size of the photon determine the type of wave and its energy.
The sun and the ER • The sun’s radiant energy • 9% of it is UV rays • 46% is visible light • 45% is infrared light
Infrared Radiation • Infrared Radiation is the portion of light just below red on the electromagnetic spectrum. • Causes molecules to vibrate this cause friction and the molecules heat up. • Most IR does not reach Earth’s surface. It is absorbed by CO2. • Some higher level radiation does hit Earth and is absorbed and reradiated back as IR. • This lead to the heating of the Earth’s atmosphere.
Visible Light • Clear Day = 90% of visible light reaches the earth’s surface. • It is blocked by dust, clouds, pollution etc. • It can energize electrons in some biochemicals = photosynthesis. • It can excite cells in our eyes causing us to see.
Ultraviolet Radiation • Stronger energy than visible light. • Three categories of UV radiation: • UV-A: • Longest wavelength, lowest energy • UV-B: • Shorter wavelength, higher energy - causes cancer. • UV-C: • Shortest wavelength, highest energy - used for sterilization • UV-A, UV-B, UV-C are mostly blocked by the ozone layer. • UV-C is absorbed by the atmosphere. • Mostly UV-A gets through to us.
UV radiation • If all UV radiation reached the Earth’s surface - the Earth would be destroyed. • However, we need some UV radiation - it helps us produce vitamin D when exposed to our skin.
The Carbon Cycle • The carbon cycle is the movement of carbon throughout the Earth’s ecosystem. • 100 yrs ago it was predicted that the level of carbon dioxide in the atmosphere due to the increase in burning of fossil fuels would be detrimental • The law of conservation of matter states that the matter can’t be created or destroyed so the amount of carbon would just keep changing forms (physical states)
The Carbon Cycle • Atmospheric “reservoirs” of Carbon: • Carbon dioxide in the air • Calcium Carbonate (CaCO3) in limestone • Natural gas (CH4) • Petroleum
The Carbon Cycle • 71% of Carbon is in the form of CO2 in ocean. • 22% is in the form of fossil fuels • The rest is in the rocks.
The Carbon Cycle - Burning Fossil Fuels • Coal: C + O2 CO2 • Natural Gas: CH4+2O2 CO2+2H2O • Gasoline: 2C8H18+25O216CO2+18H2O
Greenhouse gases and global change • The greenhouse effect is a natural and necessary phenomenon. • Carbon dioxide and water vapor are the two principle greenhouse gases. • These gases have been constant for millions of years…….until human came along.
Global warming • There are 12 trillion tons of water vapor in the atmosphere. • Human activity can effect the temp. of atmosphere. • This causes more water vapor to evaporate. • More water vapor (greenhouse gas) means more warming. • More warming means more evaporating. • More evaporating mean more warming etc. • However, increase water vapor increases cloud cover so the temperature increase is not as dramatic.
Global Warming • Carbon dioxide is similar. • If too much CO2 is added to atmosphere then stored CO2 in ice and soil could be released and the warm up continues. • Two other greenhouse gases: N2O and CH4 (methane).
Global Warming • The last ten years have been the warmest to date. • If nothing done, temp. will inc. .3C per year. • By 2100 temp will inc. by 1C per year.
Global Warming • Most scientists agree that the Earth will increase in temperature by 3-5C over the next century. • However, new data shows that the lower atmosphere is not warming as fast as the Earth’s surface. So there must be other factors affecting the warming. • El Nino • La Nina
Effects of Global Warming. • The oceans (melting polar ice caps) will rise 5 cm (about 2 in.) per decade over the next century. • Flooding in several major cities: brings disease, pestilence, wastewater. • Rain cycle and growing season would be affected • Possibility of big storms with long droughts in between. • Short winters with severe blizzards.
Preventing Global Warming • Kyoto Protocol • Developing energy efficient technologies • Focus on renewable energies.