GC 170a1 1st Edition Lecture 7 Outline of Last Lecture I Group Assignment Eco Footprint Outline of Current Lecture I The Green House effect a Shortwave vs Longwave radiation i How is the earth heated ii How are longwave shortwave emitted vs absorbed II CO2 Greenhouse gases a Structure of greenhouse gases vs non greenhouse gases i Triatomic Diatomic b Absorption spectrum i CO2 ii H2O iii N2O CH4 iv O3 III Temperature in Stratosphere Current Lecture The Greenhouse Effect I Sun emits shortwave radiation Mostly UV visible light some IR II Earth absorbs shortwave radiation earth s temperature increases III Earth emits longwave radiation Emits 100 IR radiation Wien s Law based on its temperature IV Greenhouse gases absorb outgoing longwave radiation V Greenhouse gases emit longwave radiation back towards earth These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute VI The lower atmosphere is heated CO2 greenhouse gases I Are Triatomic a They absorb and re emit IR radiation II H2O CO2 are triatomic Highest concentration ppm in the atmosphere a They are greenhouse gases b Shortwave passes through c Longwave absorbed and emited Reaction i The GHG s absorb energy 1 Causes vibration bending and rotation of atomic bonds 2 This process converts electromagnetic radiation to heat energy a Electromagnetic radiation is transmitted as a wave and a stream of particles photons b Photons interact with atoms and molecular bonds ii If there was no atmosphere then longwave radiation would be transmitted to space it would be freezing d Each molecule has a slightly different molecular structure e Each molecule absorbs slightly different wavelengths of energy i Absorption spectrum the proportion of energy absorbed by a gas at a particular wavelength f CO2 i Doesn t react with incoming shortwave radiation ii Absorbs outgoing longwave radiation g H2O i Water Vapor has broader absorption spectrum ii Absorbs a lot of longwave radiation h N2O CH4 i Narrow band of absorption ii Still very important greenhouse gas effect i Ozone O3 i Absorbs most of incoming UV good thing ii Ozone layer in the stratosphere iii Ozone in the troposphere absorbs outgoing IR III Wavelength bands where no radiation is absorbed or emitted IV N2 O2 are diatomic a They are not greenhouse gases b Shortwave passes through c Longwave passes through Why is the upper stratosphere warm I Temperature peaks above the region of highest ozone concentration II Ozone O3 concentration absorbs solar UV radiation III Converts electromagnetic radiation to HEAT
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