ASTRON 1F03 Lecture Notes - Lecture 10: Runaway Greenhouse Effect, Solar Wind, Water Vapor
18 Dec 2015
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Document Summary
Venus: hot early, so no water on surface. Earth: water dissolved carbon dioxide from atmosphere, forming limestone. Two of the most effective greenhouse gases, water and carbon dioxide, were therefore contained on earth; on venus, they were not, which meant a runaway greenhouse effect. Troposphere (surface to 10-15km altitude): temperature and pressure decline with altitude, water vapor mainly here, clouds and weather. Mesosphere (50-90km): temperature rises with altitude, ozone absorbs uv, heats stratosphere, side effects: protects life from uv, no ozone, temperature declines with altitude, upper mesosphere is coldest part of atmosphere. Thermosphere (>90km): uv radiation and solar wind can ionize atoms, solar wind = flow of particles from the sun, above is the ionosphere. Earth"s magnetic field, the magnetosphere, extends out into space. Particles from the solar wind only enter near the poles. This creates the northern and southern lights (auroras). Vertical circulation of air (convection) distributes surface heating. Global winds carry heat from hot to cool regions.
