geography: atmosphere

ozone

gas molecule made up of three oxygen atoms

function of ozone layer

filters out harmful ultraviolet radiation:

- ozone molecule absorbs UV radiation, splits into O2 and one single oxygen atom which rejoins with the oxygen molecule, forming ozone again.

what happens to the absorbed UV radiation?

gets converted into heat

ozone depletion

the thinning of the ozone layer

causes of ozone depletion

Chlorofluorocarbons (CFCs) are synthetic compounds that are very stable in the lower atmosphere

- make their way up to the stratosphere

- ultraviolet radiation in the stratosphere strikes a CFC molecule and causes a chlorine atom to break away

- chlorine atom reacts with an ozone molecule, forms chlorine monoxide and leave a molecule of ordinary oxygen

- free atom of oxygen collides with the chlorine monoxide

- two oxygen reacts -> molecule of oxygen

- the chlorine atom is released and is free to destroy more ozone

effects of ozone depletion

increased exposure to harmful UV radiation

OZONE HOLE

ozone holes are..

areas where ozone concentration drops to 220 dobson units

normal concentration of ozone

300 dobson units

remote sensing

satellites and instruments monitor ozone depletion

true or false:

UV radiation destroys and damages living tissue

true

effects of ozone depletion on humans

skin cancer

eye cataracts

increased illness- lowering of immune system

increased in incidence of malaria

effects of ozone depletion on the environment

weather patterns change

surface temperature increases

life cycle of plants change -> disrupting food chains

possible dying out of microscopic organisms (basis of food chain)

ways to reduce ozone depletion

- use ozone friendly products

- recover and recycle old CFCs when repairing refrigerators or ACs - so that they're not released into the atmosphere

- check air conditioning units in cars for leaks

- limit high-altitude flights <-- combustion in aeroplane engines reduce oxygen in the atmosphere

- stop production of CFCs and other ozone-depleting substances

- plant more trees to increase oxygen levels through photosynthesis

processes involved in the heating of the atmosphere

insolation, absorption, scattering, reflection

albedo

amount of solar energy reflected off Earth; in percentage

short-wave radiation

hot temperatures

long-wave radiation

cool temperatures

how much insolation is absorbed

70 percent:

- 51: surface

- 19: atmosphere and clouds

how much is reflected

30 percent:

- 4: surface

- 20: clouds

- 6: atmosphere

ways of heat transfer in the atmosphere

radiation (solar and terrestrial)

conduction

convection

insolation

incoming solar radiation: short-wave radiation from the sun

terrestrial radiation

Earth surface is warmed due to insolation and this causes radiation(long-wave) given off from Earth

conduction

heat transfer by direct contact of molecules in any phase(liquid/solid/gas)

convection

heat transfer through the MOVEMENT of a liquid or gas

greenhouse effect

natural heating of the atmosphere through absorption and reflection of terrestrial radiation

greenhouse gases

gases that absorb/trap heat from long-wave terrestrial radiation

examples of greenhouse gases

water vapour

carbon dioxide

positive environmental impact of the enhanced greenhouse effect

rise in global temperature:

• more of the Earth’s surface suitable for settlements and farming

• different climate zones develop

• these zones create suitable conditions for a wide range of plants and animals, leading to diverse biomes across the planet

negative environmental impact

Global warming:

• some places become too hot to grow crops

• too much or too little rain

• sea levels rise potentially causing floods

impact of the enhanced greenhouse effect, on people

• global warming/climate change means people won’t be able to utilise the various biomes like we do now

• further changes where we live, and how and where we grow food

what increases the amount of greenhouse gases?

human activities such as the burning of fossil fuels

global warming

enhances the Greenhouse Effect due to human activities(burning of fossil fuels) and causes Earth’s average temperature to rise.

horizontal differences in temperature are caused by

latitude

ocean currents

distance from the sea

winds

how does the shape of the earth affect temperature

• earth’s curvature allows the sun to give off more direct sunlight on the equator(lower latitudes)

• the poles receive more oblique sun’s rays

• less atmosphere to pass through near the equator, so less heat loss through absorption, reflection and scattering

• larger surface area for the sun to heat up near the poles

which two factors cause seasons to occur?

the Earth’s tilt on the axis and it’s elliptic movement around the sun

why do the polar regions receive little insolation even though they have long daylight hours in summer?

due to the shape of earth, there is more atmosphere to pass through and therefore there is more heat loss. + oblique sun’s rays