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 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.

Parts of a wave

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 RadiationInfrared 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

The Carbon Cycle

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

The Carbon Cycle

71% of Carbon is in the form of CO2 in ocean.

22% is in the form of fossil fuelsThe rest is in the rocks.

The Carbon Cycle - Burning Fossil FuelsCoal: C + O2 CO2

Natural Gas: CH4+2O2 CO2+2H2OGasoline: 2C8H18+25O2

16CO2+18H2O

Greenhouse gases and global changeThe 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.