ENVIRSC 1A03 Lecture Notes - Lecture 5: Solar Irradiance, Longwave, Boltzmann Constant

• School: McMaster University
• Department: Environmental Science
• Course: ENVIRSC 1A03
• Professor: Luc Bernier

Document Summary

We receive a fraction of the sun"s energy. Provides solar energy (heats up the earth + can be harnessed for other purposes) Early on in the sun"s life, we only received 70% of the energy from the sun as we receive today. The sun was much weaker early on. Earth"s temperature was cooler 4. 6 billion years ago. The earth was colder back then because of the low concentrations of radiation capturing gases in the atmosphere (greenhouse gases) The link between temperature and radiation: stefan-boltzmann equation --> e = ot^4, e = intensity of radiation emitted, t = surface temapature (k) = stefan =boltzmann constant (5. 67x10^-8 w x m^-2 x k^-4) Body that is perfectly efficient at emitting radiation. For gray bodies, stefan-boltzmann equation becomes: i = eot^4. E = emissivity factor ( =1 for black bodies) Most solids and liquids are actually graybodies. If the temperature of the sun doubled, the impact on the radiation emitted would increase by.