Index


A
Absorbance 54-55
Absorptance, defined 54
Absorption see also Cross section, absorption
- by atmospheric gases 93
- classical versus quantum-mechanical 76-78
- by harmonic oscillator 72
- by particles 110-114
Absorption coefficient
- bulk 112, 159
- defined 51
- Einstein 86, 118
- of ice and liquid water, near-infrared 285
- and imaginary part of refractive index 159
- molecular 89
- of suspension of particles 111
Absorption cross section see Cross section
Absorption length
- defined 53
- of ice 53, 261, 280
- of liquid water 53, 261, 280
Absorption line see also Line shape and Line strength
- defined 72
Absorptivity
- average 20
- defined 14
- line 108
- of a pile of plates 247
Acoustic waves 142
Aerial perspective 403
Aerosol, defined 164
Airlight see also Skylight
- defined 400
- luminance of 416
- radiance of 401
Albedo 33
- Bond 237
- of Earth 33, 232
- for single scattering see Single-scattering albedo
Alexander's dark band 434
Amplitude modulation 161
Anticorona see Glory
Antisolar point 377, 431
Arago point 377
Asymmetry parameter
- general expression for 298
- in Henyey-Greenstein function 305
- of a plate 248
- in two-stream theory 256
- of a water droplet 269
Atmospheric optical phenomena see Meteorological optics
Atmospheric optics see Meteorological optics
Attenuation
- exponential 52
- nonexponential 63-65, 116
- in nonuniform medium 56
Attenuation coefficient 265
Average, concept of 17-20


B
Babinet point 377
Backscattering
- coherent 342
- radar see Cross section
Beer's law 53, 116, 122, see also Bouguer's law
Birefringence, linear 359
- of hailstones 362, 385
- induced 359
- natural 359
- and sun dogs 362
Blackbody
- defined 13
- minimum temperature to be visible 38
Blackbody radiation 12-14
- history of 39
- without a blackbody 15-17
Blue moon and sun 174, 179
Boltzmann factor 80
Bond albedo see Albedo
Bouguer's law 53, 115
Brewster angle
- defined 364
- pseudo-Brewster angle 365
- scattering interpretation of 366-367
Brewster point 377
Brewster's law 365, 386
Brightness
- defined 204, 206
- dependence on angular size 194
- of sky 399-406, 415
Brightness temperature
- of clear sky 26-27
- of clouds 26-27
- defined 21
- of sky with zenith angle 58
- of water, directional dependence 31


C
Candela 200
Carbon dioxide
- absorption spectrum of 93
- normal modes of 83, 101
Carbon monoxide
- absorption spectrum of 93, 99
- rotational energy levels of 95
- vibrational energy levels of 95
Caustic 195, 430
Chappuis bands 100, 411
Chromaticity coordinates 218
Chromaticity diagram 218, 219
CIE 217, see also Colorimetry and Chromaticity diagram
Cloud bow 435
Clouds
- brightness variation of 440-441
- color of 259-261, 268-270, 442-444
- composition of, determined remotely 116
- emission by 26-29
- irradiance profiles in 319
- particle volume fraction of 268
Coherence 136, 175
Coherence length
- lateral 137-139
- of sunlight 139
Collisional broadening 85, see also Line shape
Color contrast, simultaneous 218
Color names 214, 216, 228
Color temperature
- of blackbody 222
- correlated 222
- of daylight 21
- defined 21
- of incandescent lamp 21
- of skylight 21
Colorimetry 216-224
- achromatic point 219
- chromaticity coordinates 218
- chromaticity diagram (CIE 1931) 219
- chromaticity diagram (CIE 1976) 223-224
- complementary colors 219
- defined 216
- nonspectral colors 219
- purity 220
- purple line 219
- spectral colors 219
- spectrum locus 219
- tristimulus values 216-217
Colors, complementary see Colorimetry
Combinations, of fundamental frequencies 82, 100
Complex variables 66-70
Continuum absorption 90, 104, 118
Contrast 196
- between object and horizon sky 416
- because of temperature differences 25
- threshold 416
Coordinate axes, transformation of 308-309
Corona 260, 427-429
- elliptical 429, 450
- in the eye 449
- from nonspherical particles 429, 449
- theory of 427-429
Critical angle 210, 390
- and sun dogs 439
Critical opalescence 153
Cross section
- absorption, of atmospheric molecules 93
- absorption, of a molecule 61
- absorption, of a particle 110
- absorption, of a water droplet over six decades 170
- absorption, of a water molecule 65
- and emissivity 65
- extinction, defined 155
- extinction, of a large particle 169
- extinction, of a sphere 166
- and molecular absorption coefficient 62, 89
- radar backscattering 168
- scattering, differential 155
- scattering, of a molecule 129
- scattering, of a molecule, and polarizability 418
- scattering, of a sphere 166
- scattering, of a water droplet over six decades 170
- scattering, total 155
- volumetric absorption, defined 111
- volumetric absorption, of a particle, approximate 121
- volumetric absorption, of a slab 112
- volumetric absorption, of a water droplet 114
- volumetric scattering, defined 156
- volumetric scattering, of a water droplet 173
- wavelength dependence of 173
Crowding 272


D
Daylight 21, 405, 447
Degree of polarization see Polarization
Detailed balance, principle of 14, 40
Dichroism
- circular 351
- linear 350
Diffraction
- many meanings of 126
- two-slit pattern 137-138
Diffuse radiation 261-263
Diffusion coefficient 297-298
Diffusion equation 297
Diffusion length
- of cloud 299
- defined 297
Diffusion theory 297-299
- boundary conditions for 299
Dipole
- electric 73
- induced 73
- magnetic 374
- permanent 73
- scattering by 127-129
Dipole moment
- electric 73
- magnetic 374
- magnetic, of oxygen 100
Directional derivative 292-293
Discrete ordinates 296, 336
Dispersion
- anomalous 162
- normal 162
- of polarization 378-379
Distribution function
- change of variable of 8
- defined 5
- distinction between point function 12
Dominant wavelength
- of blue sky 221
- defined 218
Doppler broadening of spectral lines 85, 102-103
Doppler effect 143-145, 176
Doppler shift
- blue shift 145
- longitudinal 145
- red shift 145
- transverse 145
Doubling, method of 246, 279


E
Earthshine 232
Efficiency see Efficiency factor also Cross section
Efficiency factor 111, 156
e-folding length 53
Einstein absorption coefficient see Absorption coefficient
Einstein induced emission coefficient 86, 118
Einstein spontaneous emission coefficient 86, 118
Electric field 227
Electromagnetic radiation see also Black-body radiation and Solar spectrum
- terminology for spectral regions 22
- wave versus particle description 1-4
Ellipsometric parameters 346
Ellipticity of vibration ellipse 346
Emission
- by clouds 26-29
- induced 84
- by negligibly scattering medium 310
- spontaneous 84
- stimulated 84
- in two-stream theory 277-279
Emissivity
- and absorptivity 14
- average 20
- and cross sections 65
- defined 14
- directional 29-31, 57, 238
- directional, of atmosphere 57
- directional, of liquid water 29
- and global warming 31-35
- greater than one 13, 111
- hemispherical 237
- of liquid water, normal 28
- normal 26
- of moist air, normal 28
- polarization dependence of 366, 386
- of a sphere 111
Emittance 13, 40
Energy balance see Global warming
Energy levels 78, see also Carbon monoxide
- electronic 78, 80
- excited states 79
- ground state 79
- lifetime of 79
- multiplicity of 95, 96
- populations of 96-98
- probability of occupancy 80, 87, 95, 98
- rigid rotator 83
- rotational 78, 80, 83
- vibrational 78, 80
- of water, vibrational 81
Entropy, of radiation 384, 394
Equilibrium radiation see Blackbody radiation
Extinction coefficient 156
Extinction cross section see Cross section
Extinction paradox 169


F
Far field 371
Fermat's principle 420
Fick's law 297
Field, defined 189
Fluorescence
- defined 41
- of orange vests 201-202
- of paper 203-204
Flux 206, see also Irradiance
Flux density 206, see also Irradiance
Flux divergence
- computation of by Monte Carlo method 312-313
- defined 59, 212
- of solar radiation in clear atmosphere 328
- of terrestrial radiation in clear atmosphere 328
Fog bow 435
Fraunhofer theory 427
Frequency
- beat 142
- carrier 142
- circular 2
- plasma 155
- resonant 72
- unit of 2
Frequency modulation 161
Fresnel coefficients
- for reflection 364
- for transmission 366


G
Geometrical optics 3, 429
Global warming 31-35
Glory 436-437, 450
Green flash 425-426, 449
- demonstration of 449
- role of physiology in 426, 449
Green rim of sun 426
Green thunderstorms 441-445, 451
Greenhouse effect 37
Group velocity 162-163, 178


H
Halo
- 22° 439
- 46° 440
- crystal size responsible for 440, 451
- frequency of occurrence of 440, 451
- lunar 439
Handedness, of vibration ellipse 346
Harmonic approximation 74
Harmonic oscillator 70
- energy levels of, quantized 77
Harmonic wave 133
Hartley bands 100
Heating rate profiles, atmospheric
- for absorption of solar radiation 331
- for absorption of terrestrial radiation 331
Henyey-Greenstein see Phase function
Herzberg band 102
Heterodyning 143, 176
Homonuclear molecule 81
Horizon sky
- color of, role of particles 406-408, 447
- radiance of 401, 403-405
Hue 218
Huggins bands 100


I
Ice
- absorption spectrum of, visible 261
- absorption spectrum over several decades 53
- bubbly, color of 273-275
- in near-infrared, compared with that of liquid 285
Illuminance 206
Image, defined 24
Impact parameter 430
Index of refraction see Refractive index
Infrared-active gases 33, 81
Insulation, basic physics of 37
Intensity 204
Interference
- constructive 134
- defined 134
- destructive 134
- of orthogonally polarized waves 349
- of waves in different directions 146-148
- of waves with different frequencies 136
- when it can be ignored 249-250
Inversion, of measurements 164, 245
Iridescence 260, 429
Iridescent clouds 429
Irradiance
- defined 207
- diffuse transmitted 261-263
- Monte Carlo calculation of 312
- profiles 317-320
- from quadrature 310
- from radiance 207
- vector 212, 295
Isotope shift, of heavy water 82, 121
Isotropie
- medium 256, 295
- radiation 59, 256, 295
- scattering 256, 374


J
Jacobian, of transformation 8


K
Kirchhoff's law 15, 40, 89, 277
- applied to averages 20
- validity of 20, 40
Koschmieder's law 416, 448


L
Lambert's law see Bouguer's law
Lambertian detector 209
Lapse rate of temperature
- average 419
- mid-latitude summer 91
Laser speckle 139, 176
Line absorptivity 108
- of carbon dioxide 110
Line shape 85, 90, 102-104
- Doppler broadened 102
- foreign broadened 102
- Lorentz 73
- natural 102
- and remote sensing of water vapor 105-106
- self-broadened 102
- Voigt 103
Line strength 90
Longwave radiation, defined 22
Lorentz force 227
Lorentz line shape see Line shape
Lorenz-Mie theory 177
Luminance 200
Luminescence
- defined 41
- and fluorescence, distinction between 41
Luminous efficiency 11, 200


M
MacAdam ellipses 224, 229
Magnetic field 227
Marshall-Palmer distribution see Raindrops
Maxwell-Boltzmann distribution 6, 38, 39
- for molecular velocity component 145
- in two dimensions 122
Mean free path, photon
- absorption 254
- probability distribution for 253-254, 301-303
- scattering 254
- total 254
Mean-value theorem 5, 190
Mesopic vision 200
Metamerism 218
Meteorological optics 397, see Airlight, see Corona, see Glory, see Green flash, see Halo, see Iridescent clouds, see Mirages, see Rainbow, see Sun dog
Methane
- absorption spectrum of 93
- normal modes of 101
Mie theory 165
Mirage
- defined 418
- extraterrestrial 423-425
- inferior 422
- multiple image 422, 448
- superior 422
- terrestrial 418-423, 448
Mock sun see Sun dog
Molecules, scattering by see Rayleigh's scattering law
Monte Carlo method
- atmospheric applications of 315-335
- basic principles of 300-315
Moon illusion 418, 448
Mueller matrix 367
- for specular reflection 368
Multiple scattering see also Radiative transfer
- in an absorbing medium 264-268
- defined 241
- medium, coherent 241
- medium, incoherent 241


N
Neutral points 377
Nitrous oxide
- absorption spectrum of 93
- normal modes of 101
Normal coordinates, of harmonic oscillator 76
Normal frequencies
- of carbon dioxide 83, 101
- of carbon monoxide 101
- of harmonic oscillator 76
- of methane 101
- of nitrous oxide 101
- of ozone 101
- of water molecule 81, 101
Normal modes, of harmonic oscillator 76


O
Optical beating see Heterodyning
Optical constants see also Refractive index
- compendium of 178
- defined 160
- of water 160
Optical depth 256
- absorption 256
- distinction between optical thickness 257
- scaled 257
- scattering 256
- total 256
Optical mixing see Heterodyning
Optical thickness
- absorption 55
- along an arbitrary path 401
- of a molecular atmosphere 400, 402
- of a molecular atmosphere, approximate expression for 402
- of a pile of plates 245
- scattering 257
- tangential 403
Optically homogeneous medium 51
Optically smooth surface 2
Optically thick medium 258
Overtones, of fundamental frequencies 82, 100
Oxygen
- absorption optical thickness for Earth's atmosphere 321
- absorption spectrum of 93
Ozone
- absorption spectrum of 93
- and blue of twilight sky 409-415
- Chappuis bands of 411
- vertical profile of 411


P
Parhelia see Sun dog
Particle, defined 60
Phase, of wave, defined 133
Phase function
- defined 295
- Henyey-Greenstein 304
- Henyey-Greenstein, compared with Mie theory 307
- normalization of 295
Phase matrix 383
Phase speed 130, 133, 161
- greater than c 161
Phasor 135
Photoelectric effect 3, 37, 38
- without photons 3, 38
Photometry, defined 185
Photon
- angular momentum of 1, 45
- energy of 1, 2
- linear momentum of 1, 45
- mass of 1, 37
- path length distributions of 315, 320
Photopic vision 200
Pilot's bow see Glory
Planck distribution 6, 8, see also Blackbody radiation
- as a function of circular frequency 6
- low-frequency limit 7
- as a function of wavelength 9
- large-wavelength limit 9
Planck function see Planck distribution
Plane of incidence 362
Plane wave, defined 133
Plane-parallel medium 59, 252
Plasma frequency 155
Polarizability 418
Polarization
- change upon specular reflection 362-365
- circular 346-347
- complete 347
- degree of light scattered by water droplets 379
- degree of, circular 357
- degree of, elliptical 357
- degree of, linear 357
- degree of, linear, upon scattering by a dipole 373
- degree of, linear, upon specular reflection 369
- discovery of by Malus 385
- dispersion of 378
- elliptical 347
- linear 347
- and navigation by bees 383, 387
- and navigation by Vikings 383, 387
- partial 347, 354
- of skylight 374-377, 386
- unpolarized light 354-355
Polarizing angle see Brewster angle
Polarizing filter
- circular 351
- linear 350
Poynting vector 185, 227, 345
- time-averaged 349
Poynting's theorem 227
Precipitable water, defined 28
Pressure broadening see Collisional broadening
Probability density, defined 5
Purity 218
- of blue sky 221
- chromatic 221
- excitation 220
Purkinje effect 200, 228
Pyranometer 232


Q
Quadratures 296
Quarter-wave plate 360
Quasi-monochromatic radiation 355


R
Radar reflectivity, defined 168
Radiance
- of airlight and skylight 399-409
- of cumulus clouds 405
- defined 189-191
- of finite cloud 326
- of horizon, relative to zenith 403-405
- invariance of 191-192, 294
- of isotropic radiation field 207
- and luminance 200
- mean 295
- Monte Carlo calculation of 313-315
- of objects under water 199, 209-211
- changes upon specular reflection and refraction 196-200
Radiation see Electromagnetic radiation
Radiation pressure 47, 184
Radiation torque 184
Radiative balance see Global warming
Radiative reaction 127, 175
Radiative transfer
- integro-differential equation for 294
- line-by-line 92, 117
- N-stream equations for 291-292
- two-stream equations of 255-256
Radiometry, defined 185
Rainbow
- color separation of 434
- complete (360°) 431-432
- double 432
- infrared 450
- primary 430-431
- secondary 430, 432
- supernumerary bows of 435, 450
- tertiary 450
Rainbow angles 430
Raindrops
- shape of 435
- size distribution for 42
Rayleigh's scattering law 128, 398, 446
Reflection
- by clouds 259-260
- diffuse 197, 208
- by objects when wet 275-276, 281
- by paint 271-272
- by a pile of plates 242-249
- by a plane-parallel medium according to two-stream theory 258
- scattering interpretation of 126, 175
- by a slab 156-158
- by snow 272-273
- specular, law of 363
- specular, in photon language 2
- specular, in wave language 2
- total internal 390
Reflectivity
- of absorbing plane-parallel medium 267
- coherent 157, 249
- defined 15
- incoherent 250
- of laterally finite cloud 324
- of a pile of plates 242-249
Refraction
- atmospheric 418-426
- double 360, 385
- law of 363
Refractive index
- of air at sea level 419
- of air, variation with height 419
- and colors of rainbows 434
- complex, defined 159
- of composite media 179
- of a gas 418
- and mass density 161
- and phase speed 161-163
- of water 160
Retardance see Retarder
Retarder, linear 359
- fast axis of 359
- quarter-wave plate 360
- retardance of 361
- slow axis of 359


S
Saturation 218
Scale height 402, 419
- for molecules 409
- for particles 409
- for water vapor 121
Scattering
- by air 151-153
- angular dependence of water droplets 174
- coherent 125
- conservative 257
- cross section 129
- defined 125
- by a dipole 127-129
- elastic 125, 128
- by fractal-like particles 178
- by hexagonally shaped ice crystals 437-440
- by liquid water 153
- multiple, defined 241
- multiple, by a pile of plates 241-249
- by nonspherical particles 178, 429
- by oblate raindrops 435
- phase shift upon 148-151
- quasi-elastic 128
- by an arbitrary sphere 165-168
- by a small sphere 168
- wavelength dependence of, by oil droplets 173
Scattering angle 150
Scattering coefficient 155
- in Mie theory 166
Scattering matrix
- for arbitrary sphere 378
- for spherically symmetric dipole 373
Scattering plane 370
Schumann-Runge bands 102
Scotopic vision 200
Selection rules 82, 83
Shortwave radiation, defined 22
Signal speed 163, 178
Single-scattering albedo
- defined 257
- of a plate 248
- of a water droplet 269
Size constancy 194, 227
Size parameter, defined 167
Sky color, theories of 398
Skylight see also Airlight
- polarization of 374-377
- spectrum of 214, 399, 447
- spectrum of, for hypothetical molecular atmospheres 405
Snel's law 363
- generalized to a stratified medium 421
Snow
- color of 273-275
- reflection by 272
- reflection, reduced by soot 273
Solar constant see Solar irradiance
Solar irradiance 23
Solar point 377
Solar spectrum 23, 24, 41
Solid angle
- defined 187
- of sun at Earth 187
Soot 273
Speckle see Laser speckle
Spectrum locus 219
Standard observer, CIE 217
Stefan-Boltzmann constant 12
Stefan-Boltzmann law 12
Stigler's law of eponymy 53, 115
Stokes parameters 349-356
Stokes vector 352
Subsun 198, 228
- and UFOs 198
Sun, color of low 409
Sun dog 437-440
Sunrise and sunset, colors of 408-409
Supernumerary bows see Rainbow
Superposition, of waves 134-136
Surfaces of constant phase 133
Sylvanshine 451


T
Terrestrial radiation, defined 22
Time-reversal symmetry 14, 40
Tip angle 198, 439
Titanium dioxide, particles in paint 271, 281
Transmission axis of linear polarizing filter 350
Transmissivity
- of atmosphere 94
- defined 32
- of a pile of plates 246, 249
- of plane-parallel medium, role of multiple scattering 259, 260
- of plane-parallel medium, two-stream and Monte Carlo compared 316
Tristimulus values see Colorimetry
Twilight 409-415, 447
Two-stream theory 254-268
- compared with Monte Carlo 316, 317


U
Umov's rule 391
Uniform chromaticity scale 223


V
Vibration ellipse 346, 347, see also Polarization
- at different scattering angles, for a sphere 380
Vibration-rotational bands 83
Visibility 415
Visual range 415
- and highway safety 448
- maximum, at sea level 417
Voigt line shape see Line shape
Volumetric absorption cross section see Cross section
Volumetric scattering cross section see Cross section


W
Water
- absorption spectrum of ice 53, 261, 280
- absorption spectrum of liquid 53, 160, 261, 280
- absorption spectrum of vapor 65, 93
- color of 82-83, 117
- normal modes of 81, 101
Water vapor
- remote sensing of 105-106, 119
Water vapor, and visibility 417
Wave
- acoustic 142-143
- homogeneous 348
- inhomogeneous 348
- on a string 129-134
Wave equation
- one-dimensional 130
- three-dimensional 141
Wave vector 348, 362
Wavenumber 10, 79
White, absolute, nonexistence of 224-226
Whiteout 24
Wien's displacement law 10
Window region 45
- of Earth's atmosphere 92