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GROUP : 3
HARSH N. PATEL : 13 ME 103BHAUTIK B PATEL : 13 ME 094DARSH A NAIK : 13 ME 078DHRUVAL PATEL : 13 ME 101CHIRAG PATELPARTH PATEL
Principal Atmospheric Gases
GAS MASS
Nitrogen 75%Oxygen 23%Argon 1%Water Vapor 0.3%CO2 0.06%
Greenhouse gases
Earth’s Energy BalanceEarth’s Energy Balance
Energy entering top of atmosphere
Energy entering the Earth’s surface
= Energy leaving top of atmosphere= Energy leaving top of atmosphere
= Energy leaving Earth’s surface= Energy leaving Earth’s surface
Solar Radiation (Sunlight)
Sunlight is primarily made up of the following:– Visible Light (44%)Visible Light (44%)– Infrared Radiation (48%)Infrared Radiation (48%)– Ultraviolet Radiation (7%)Ultraviolet Radiation (7%)
Unit: 1 m =
0.000001 m
Energy from the Sun
Obviously, the Sun provides the Earth with it’s energy. The question is, how much of the Sun’s energy does the Earth get?
Sun’s energy is either– Scattered (reflected away) or– Absorbed
Scattering happens by bouncing off – Particles in the atmosphere– Earth’s surface
Absorption happens when certain gases absorb the energy– The reality is the only certain gases absorb certain
wavelengths.
Incoming solar radiationIncoming solar radiation
Each ‘beam’ of incoming sunlight can be either:– Reflected back to space:
CloudsClouds AtmosphereAtmosphere SurfaceSurface
– Or absorbed; either by atmosphere (e.g. clouds or ozone) or Earth’s surface.
AlbedoAlbedo
Absorption of radiation
Absorption of shortwave radiation by atmospheric gas molecules is fairly weak; – most absorption of shortwave radiation occurs at the
Earth’s surface.
Most gases do not interact strongly with longwave radiation, however
– Greenhouse gas molecules absorb certain Greenhouse gas molecules absorb certain wavelengths of longwave radiation.wavelengths of longwave radiation.
Longwave radiation is emitted from surface.
Some surface radiation escapes to space
Most outgoing longwave is absorbed in atmosphere (by greenhouse gases)
Greenhouse gases emit longwave upward and downward
Some atmospheric radiation escapes to space
Some atmospheric radiation is absorbed at the surface
Greenhouse EffectGreenhouse EffectSequence of steps:
1.1. Solar radiation absorbed by earth’s surface.Solar radiation absorbed by earth’s surface.
2.2. Earth gives off infrared radiation.Earth gives off infrared radiation.
3.3. Greenhouse gases absorb some of the Earth’s infrared radiation.Greenhouse gases absorb some of the Earth’s infrared radiation.
4.4. Greenhouse gases (water and CO2) give off infrared radiation in Greenhouse gases (water and CO2) give off infrared radiation in all directions.all directions.
5.5. Earth absorbs downward directed infrared radiationEarth absorbs downward directed infrared radiation
Result: warmer surface temperature
Earth’s Greenhouse Effect
Without the greenhouse effect, the surface temperature of Earth would be – Very Cold (-18°C)
Greenhouse gases play an important role in shaping climate.– More GHGs – warmer climateMore GHGs – warmer climate– Less GHGs – cooler climateLess GHGs – cooler climate
Activity
Draw a diagram showing how the earth is heated by the Sun.
Include arrows and/or lines to indicate the ‘Energy Balance” of the earth.
Energy Balance – Energy coming in and energy going out.
In your diagram, include how clouds absorb, reflect and emit energy.
1. What percentage of the sun’s radiation is a) absorbed by the Earth’s surface?b) absorbed by the atmospherec) reflected out to space?
2. What percentage of the energy received by the earth’s surface comes directly from greenhouse gas emissions?
3. If the sun’s radiation was to increase by 10%, how would the following energy units change (increase, decrease or stay the same)a) Energy gained by the Earth’s surface.b) Energy lost by the Earth’s surface.c) Energy emitted by greenhouse gases.d) Energy lost to space.
Activity 2