Lecture Week 2: Topics

[NOTE: AJJ12 = Ahrens, Jackson & Jackson (2012). 1st Canadian Edition
AJJ16 = Ahrens, Jackson & Jackson (2016). 2nd Canadian Edition
REF: All of AJJ12 / AJJ16 Chapter 2 is required for weeks 1 to 3 Extra Lecture Notes]

Radiation; Terms and Definitions

[REF: AJJ12 - Ch 2 p 41, 55-60 / AJJ16 Ch 2 p 40-41, 47-49]

• Spectrum
• Nature of radiation: waves and photons
• K,L,Q^* : symbols used for shortwave, longwave, and net radiation
• Radiation balance equations

Measurement of Radiation

• devices
• principles of measurement

Radiation Laws

[REF: AJJ12 - Ch 2 p 42-44 / AJJ16 Ch 2 p 41-44, 47-49]

• Conservation of Radiant Energy
• Planck's Law
• Wien's Law
• Stefan-Boltzmann's Law
• Kirchhoff's Law

Shortwave Radiation

[REF: AJJ12 - Ch 2 p 45-53 / AJJ16 Ch2 p 44-50]

• Sun-Earth geometry [REF: AJJ16 - CH 3, p. 64-70; AJJ12 - CH 3, p. 66-73; Active Figure 3.11 Sun's path in different seasons and latitudes
  • seasons
  • diurnal
  • solar declination
  • ``beam spreading'' / Cosine Law Active Figure 3.4 Cosine Law of Illumination
• Attenuation [REF: AJJ16 Active Figure 2.12 Selective Absorption
  • Absorption
  • Scattering - Rayleigh, Mie, Non-selective
  • Reflection - albedo
• Blue skies / red sunsets / white clouds
• Absorption of radiation by gases in the atmosphere
• Atmosphere is a selective absorber - greenhouse effect REF: AJJ16 - Active Figure 2.13 Greenhouse effect
• Surface shortwave budget
• Solar energy distribution in E-A

Longwave Radiation

[REF: AJJ12 - Ch 2 p 49-61 / AJJ16 Ch 2 p 47-57]

• Longwave (IR)
• Application of Steffan-Boltzmann Law
• Longwave radiation budget
• Applications: minimum temperature / frost
• Clear vs Cloudy nights

Cloud Identification and Types

[REF: AJJ12 - Ch 5 p 141-15, 153-159 / AJJ16 Ch 5 p 135-141, 144-147]