Class Notes (834,241)
United States (323,678)
Geography (207)
GEOG 1112 (23)
Lecture 5

GEOG 1112 Lecture 5: Radiation Earth Sun (Part 2) Global Energy Balance

4 Pages
Unlock Document

GEOG 1112
James Shepherd

LECTURE 5 | RADIATION EARTH SUN (PART 2) GLOBAL ENERGY BALANCE Atmospheric Influences on Insolation • Solar radiation at the top of the atmosphere does not pass unimpeded through the atmosphere: o Absorbed o reflected or scattered o transmitted • They affect the amount of radiation received at the surface. • Absorption o Particular gases, liquids, and solids in the atmosphere reduce the intensity by absorption. o Less energy is transferred to the surface. o Atmospheric gases are overall poor absorbers of energy. • Absorption & Emission o If an object radiates more energy than it absorbs, it cools. o If it absorbs more than it radiates, it warms. o Review - Kirchhoff’s Law. Black Body & Selective Absorbers • Black Body: A hypothetical body that is a perfect absorber and emitter of radiation (sun) • Selective Absorber: any object that absorbs some types of radiation but not others. (atmosphere, clouds, glass, snow) Selective Absorbers • The gases in the atmosphere are good at absorbing some wavelengths of radiation but not others. • This has an important impact on our energy balance. • Visible radiation is transmitted well • Some ultraviolet (UV) is absorbed by ozone in the stratosphere • Infrared is absorbed well by the “greenhouse gases”--??? • The atmospheric window is a region (8-11 μm) where the atmosphere does not absorb infrared radiation well. Greenhouse Effect • Water Vapor • Carbon Dioxide • Methane • No Greenhouse: 18oC • Greenhouse: 15oC • It is a natural phenomena o not to be confused with Global Warming! o without it, the Earth’s average temperature would be -18oC (0oF) instead of 15oC (59oF) Venus & Runaway Greenhouse Effect • Surface temperature: (480 oC or 900 oF) • 97% of atmosphere is CO2 • Compared to 0.040% on Earth. Atmospheric Influences on Insolation • Reflection o Energy is redirected by objects through reflection without being absorbed. o Albedo is the percentage of energy reflected by an object. o Specular reflection is reflection of energy as an intense beam. • Scattering o Energy reflected as disperse energy into less intense beams is diffuse reflection, or scattering. o Gases in the atmosphere scatter radiation. o Energy that reaches the surface is scattered and different in intensity from direct radiation. o Scattering agents smaller than 1/10 the wavelength of incoming radiation is known as Rayleigh Scattering. o Partial to shorter wavelength energy. o Rayleigh Scattering results in our blues skies. It’s why our skies are blue to the human eye. o Mie scattering, scattering sunlight, is pre
More Less

Related notes for GEOG 1112

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.