This document discusses electromagnetic radiation (EMR) and its interaction with the atmosphere. It covers the following key points: 1) EMR can be described as waves with different wavelengths that determine their energy content. Shorter wavelengths like gamma rays have higher energy. 2) The atmosphere only allows certain wavelengths to pass through in "atmospheric windows" while absorbing others. Gases like oxygen, nitrogen, ozone, carbon dioxide and water vapor are significant absorbers. 3) Factors like albedo, scattering, temperature inversions, and cloud cover influence the transmission and absorption of EMR and impact atmospheric temperatures.

1. Insolation and Temperature
Chapter 4

2. Electromagnetic Radiation (EMR) can be described as waves.
Note the generation of a magnetic field at right angles to an electrical
field and both are perpendicular to the direction of EMR propagation
http://micro.magnet.fsu.edu/primer/java/electromagnetic/index.html

3. The wavelength (λ) of EMR is directly related to the amount of
NRG in the radiation.
Short (λ) (e.g. gamma rays) have a higher NRG content
Long (λ) (e.g. thermal or microwave (Radio) have a lower NRG
content
As the velocity of the
propagation of EMR
(the speed of light) is
believed to be a
constant (c)
The number of waves
to pass a single point
in a given period (the
frequency, v) is much
higher for shorter λ
radiation

5. Atmospheric Windows
Some EMR passes through the atmosphere with no interference (an ‘atmospheric
window’
Some EMR is absorbed (or blocked) by components in the atmosphere
The most significant absorbers of EMR in the atmosphere are O2
, N2
, O3
, CO2
, H2
O

6. Gamma radiation, X-rays, and UV radiation absorbed
in the upper atmosphere
Water vapor and Carbon Dioxide absorb portions of
the EM spectrum in the thermal portions of the
spectrum

8. Atmospheric scattering: (skylight or haze)
Rayleigh scatter (molecular scatter) primary factor in upper atmosphere (why the sky
is blue)
Mie scatter (non-molecular scattering, water/ice/salt/smoke) primarly in lower
atmosphere

10. When the sun is at very low angles, virtually all the shorter λ EMR is
scattered, allowing only the longer, lower NRG waves (reds) to pass
through.

14. Of the incoming EMR, a significant portion is simply reflected back into
space… Albedo

15. Clouds and Ice have an Albedo approaching 100%

16. Global albedo is not constant… but the overall average is 35%

17. The atmosphere is heated primarily from below… from the surface.

19. Adiabatic cooling and the inverse… Adiabatic warming

22. Note the influence of clouds… which interrupts the latitudinal patterns

30. 45 degrees N… halfway between equator
and pole

32. 57.5 degrees North (same latitude as
Moscow and Hudson’s Bay… semi-
tropical gardens on the coast of
Scotland

34. Normal Atmospheric Conditions…

35. Temperature Inversion… warmer air slides over the cool air at the surface
trapping the surface air beneath a very stable upper air mass