The living environment: The atmosphere

The gases surrounding the Earth. Different layers are characterised by their temperature, density, turbulence and composition.

Nitrogen = 78% Oxygen = 21% Other gases etc co2, water vapour, argon = 1%

Sunlight that reaches a particular location.

UVA = 5% absorbed = harmless UVB = 95% absorbed = harmful UVC = 100% absorbed

1) 2) 3) UVA 320-400nm not absorbed by O3 or diatomic oxygen UVB 280-320nm Almost fully absorbed by O3 UVC <280nm completely absorbed by ozone and diatomic oxygen (O2)

UVB is a cause of melanoma and other types of skin cancer If UVB is not absorbed in the atmosphere then it will reach the Earth’s surface and may be absorbed by living cells. The energy of the UVB’s absorbed and some is converted to chemical energy as it breaks up biological molecules causing skin damage, DNA damage, skin cancer, cataracts, leaf tissue damage and reduced photosynthesis and damage to marine organisms such as algae, corals and planktonic organisms

UVB and UVC has also been linked to damage to some materials, crops and marine organisms

The sun emits high energy short wavelength light (UV) the stratospheric ozone layer absorbs 50 % of UV through chemical reactions the rest passes through. Some UV is reflected by the given albedo of clouds and ice. The rest passes through and is reflected from the earth this lowers its energy to long wavelength and low energy IR radiation and the tropospheric greenhouse gases absorb most of this radiation.

-Troposphere - 10KM - where weather happens higher up the colder it gets greenhouse gases -Stratosphere - 50 KM - heated by UV absorption, primarily in the ozone (O3) layer hotter the higher up you go (heated by UV absorption) -Mesosphere - 80KM - cooler intermediate region meteors burn up here as low as -100 degrees centigrade -Thermosphere - 500 - 1000 km - heated by UV & X-ray photons international space stations orbits here aurora (northern lights) 500- 2000degrees centigrade and higher

-Gases for natural processes -Absorption of electromagnetic radiation from the sun -Delaying the escape of infrared energy. -Heat distribution. -Ocean currents -Transport of water vapour. -Gases for human exploitation.

Contains C, O, H and N, needed to make biological molecules used by living organisms. (photosynthesis and respiration)

ozone layer prevents harmful radiation causing life to mutate and heats up earth warm enough to support life

emitted infrared from the earth is absorbed by atmospheric gases increasing the temperature of the atmosphere.

Atmosphere is heated by the warm surface of the Earth. The heat is distributed by warm winds. (gulf stream)

winds blowing over the oceans creates currents that distribute heat by carrying warm water and moves nutrients and carbon in the water.

winds transport water vapour to areas that would otherwise get little or no precipitation. (constants temperature and weather cycle)

atmospheric gases are extracted by humans and used for various processes. (allows industry)

Energy from the sun is generated through nuclear fusion Energy released is in the form of electromagnetic radiation which travels as waves away from the sun at the speed of light

Short Wave = More energy Arrives first AKA UV light Long Wave = Less Energy Reflected by earth AKA Infrared

Transmission Absorption Reflection without this the mean temperature of the Earths surface would be 36degrees centigrade colder than it actually is.

Electromagnetic energy and visible light is able to pass through the atmosphere and reach the Earth’s surface Visible light, largely passes (or is transmitted) through the atmosphere.

UV -absorbed by ozone (50% on way in) IR - Absorbed by gases in the atmosphere (on way out) (greenhouse gases) Water Vapour Carbon Dioxide Ozone (O3)

-The surface of the Earth has a given albedo -When light is reflected it it is sent back into space -The wavelength increases meaning it struggles to leave through the atmosphere

The solar radiation which makes it to Earth’s Surface And gets trapped by greenhouse gases (AQA “Sunlight that reaches a particular location.”) The Sun’s energy enters the atmosphere, clouds reflect some of it back. Only 50% reaches the Earth’s surface = it can pass through the denser gases because of its short wavelength, Energy is then reflected back towards space but at a longer wavelength. (Infrared) It has difficulty travelling through the denser greenhouse gases and so the atmosphere absorbs the heat warming the lower atmosphere.