GC 170a1 1st Edition Lecture 7 Outline of Last Lecture I. Group Assignment (Eco-Footprint)Outline of Current Lecture I. The Green House effecta. Shortwave vs. Longwave radiationi. How is the earth heatedii. How are longwave/shortwave emitted vs. absorbedII. CO2 & Greenhouse gasesa. Structure of greenhouse gases vs. non-greenhouse gasesi. Triatomic – Diatomicb. Absorption spectrumi. CO2ii. H2Oiii. N2O & CH4iv. O3III. Temperature in StratosphereCurrent LectureThe 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 radiationV. 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 heatedCO2 & greenhouse gasesI. Are Triatomica. They absorb and re-emit IR radiationII. H2O & CO2 are triatomic (Highest concentration, ppm, in the atmosphere)a. They are greenhouse gasesb. Shortwave passes throughc. Longwave absorbed and emited (Reaction)i. The GHG’s absorb energy1. Causes vibration, bending and rotation of atomic bonds 2. This process converts electromagnetic radiation to heat energya. Electromagnetic radiation is transmitted as a wave and a stream of particles (photons)b. Photons interact with atoms and molecular bondsii. 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 energyi. Absorption spectrum: the proportion of energy absorbed by a gas at a particular wavelengthf. CO2i. Doesn’t react with incoming shortwave radiationii. Absorbs outgoing longwave radiationg. H2Oi. Water Vapor has broader absorption spectrum ii. Absorbs a lot of longwave radiationh. N2O & CH4i. Narrow band of absorptionii. Still very important greenhouse gas effecti. Ozone (O3)i. Absorbs most of incoming UV (good thing)ii. Ozone layer in the stratosphereiii. Ozone in the troposphere absorbs outgoing IRIII. Wavelength bands – where no radiation is absorbed or emitted IV. N2 & O2 are diatomica. They are not greenhouse gasesb. Shortwave passes throughc. Longwave passes throughWhy is the upper stratosphere warm?I. Temperature peaks above the region of highest ozone concentration II. Ozone (O3) concentration absorbs solar UV radiationIII. Converts electromagnetic radiation to
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