ENVS 2270 Lecture Notes - Lecture 3: Global Dimming, Soot, Facula
23 Feb 2017
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Document Summary
Incoming sunlight is short wave radiation: shorter wavelengths are more energy intensive than long waves. Earth is in radiative equilibrium when the flow in = the flow out. Greatest intensity from sunlight in the uv, visible and infrared parts of the spectrum. Average intensity of solar energy reaching the top of the atmosphere directly facing the sun is -1,360 wm: average total solar irradiance of the whole planet is actually -340 wm though. )t"s a sphere, so as we move away from the equator energy is diluted. Half of the planet is not facing the sun at all times. 23% is absorbed in the atmosphere by clouds and gasses. 48% is absorbed by the surface of the earth. Earth"s atoms and molecules absorb radiation and convert it to kinetic energy = solar heating. Then they radiate thermal energy (heat) = radiative cooling.
