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Ozone 6.1 - Intro to the atmosphere - Coggle Diagram
Ozone 6.1 - Intro to the atmosphere
It is a dynamic system - made up of inputs (solar energy), outputs, flows and storages. Overtime the atmosphere has changed. This is dependant on the biotic components inhabiting Earth.
Composition
Nitrogen: 78%
O2: 21%
CO2, Argon etc. : 1%
History
HADEAN ERA
: Earth was formed 4.6 billion years ago. There were extreme temperatures leading to inability to sustain life. The atmosphere predominately consisted of H and Helium gases. Name resembles Hades due to hellish environment.
ARCHEAN ERA:
4 to 2.5 billion years ago. Large oceans were formed. About 3.8 billion years ago, the first sign of life was created. Bacteria that survived anaerobically (cyanobacteria), however, overtime this bacteria began utilising light energy for energy leading to oxygen created as a by-product.
PROTEROZOIC ERA
: 2.5 billion to 542 million years ago. CO2 levels decreased and O2 increased. the formation of the ozone occured. Life was restricted to the ocean unit the ozone layer was fully formed shielding earth from harmful UV rays.
PHANEROZOIC ERA
: 500 million years ago to now. First green plants grew.
Stratosphere
10-50 km above sea level.
Absorbs UV radiation. Temp = -60°C in the lower part of the stratosphere, shielded by the ozone layer but then increases with altitude.
Troposphere
Layer closest to the Earth - inhabits humans = 0-10 km
The Earth's surface absorbs solar radiation = heats the atmosphere. Weather occurs here, most interactions.
The greenhouse effect occurs and helps regulate the Earths temperatures.
Greenhouse effect
When energy from the sun enters the Earths atmosphere as short wave radiation some is absorbed by the Earth's surface. This leads to the surface heating up and the radiation to be emitted back to the atmosphere as long wave radiation.
When there are NO GHG
, the heat would be radiated back into spaceresulting in an average global temperature of about -18°C
In the presence of GHG's
, the long wave radiation is absorbed by the gases resulting in warming of the atmosphere to an average global temperature of around 15°C.
Not all radiation reaches Earth,s surface, some is directly reflected back into the atmosphere e.g. reflected off of clouds, ice caps, snow etc.
Main GHG's
Water vapour:
the most abundant, rising temp leads to rising water vapour leading to rise in temp = a POSITIVE FEEDBACK LOOP
Carbon Dioxide:
Increased by burning of fossil fuels, respiration, volcanic activity and deforestation. Plants and trees act as carbon sinks removing CO2 from the atmosphere and storing it in the form of biomass, hence deforestation leads to more CO2 = warming
Methane
: From emissions of livestock, rice cultivation, fossil fuels.
CFC's and HCFC's
: used as liquid coolants (in refrigerators and air conditioning systems), in the production of plastic foam and as industrial solvents = less ozone = more UV radiation
Mesosphere
From 50 to 80km above sea level
Coldest part of the atmosphere with temp falling to -100°C.
Thermosphere
80km to 500/1000km above sea level
UV and X-radiation from the sun is absorbed which breaks apart molecules into atoms
Temp increases with height reaching 2,000°C+. The heat causes the layer to expand hence, variation in depth overtime from 500 to 1,000km.
Consists of the Ionosphere:
An area where particles are electrically charged.
Albedo
A measure of the reflectivity of a surface. When applied to Earth it's a measure of how much of the Sun's energy is reflected back into space
More water vapour in the atmosphere means more cloud formation. More clouds lead to increased albedo of the earth.
About 30% of incoming solar energy is reflected back to space.