GC 170 1st Edition Lecture 8Outline of Last 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 StratosphereOutline of Current Lecture II. Greenhouse affecta. IR Bandsb. No Greenhouse gases?III. Energy Budgeta. Balance between incoming/outgoingb. Balance budget definitionc. Albedoi. High/Lowd. 30% ruleThese 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.Current LectureI. Greenhouse effect and absorption spectruma. A part of the earth’s energy budget: A system of energy fluxes representing whether energy is reflected and absorbed from different surfaces and the atmospherei. Absorb longwave radiation (IR) from the earth surface ii. Each molecule absorbs slightly different wavelengths of energyiii. The molecule bends, vibrates and rotates 1. Radiating heat and emitting longwave IRb. A bunch of greenhouses combine to absorb and emit longwave radiation, and UV radiationc. The blue area in an IR band: how the atmosphere absorbs and emits longwave radiationd. Atmospheric window: no greenhouse gases that absorb that specific radiation wavelengthe. If there was no greenhouse gases, all longwave radiation would be transmitted to spacei. Earth would be freezingII. Energy Budgeta. Balance between incoming solar energy and outgoing radiation emitted by earthb. Budget: list of incoming and outgoing expenditures i. Balanced: when the incoming and outgoing are equalc. Budget with no greenhouse gasesi. Most of solar energy is absorbed but 30% is reflected off earth and cloudsii. Some surfaces are more reflective than othersd. Albedoi. The fraction of sunlight (energy) that is reflected by a surfaceii. Depends on the properties of the surface 1. Dark land surfaces (forested) have an equal albedo to water2. Cloudsa. They are bright white i. High albedo and reflect incoming solar radiation clouds b. They absorb outgoing IR i. Contribute to the greenhouse effectc. Water vapor greenhouse gasiii. High albedo: very reflectiveiv. Low albedo: low reflectivee. 30% of incoming radiation is reflectedi. Measurements are made at the top of the atmosphere and at the surface (by humans)sattelitesii. Even with an atmosphere, a lot of longwave energy (IR) is radiated out
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