20
Pat Arnott, UNR, ATMS 749 Dipole in Abstract Fractal Art From: http://www.raygirvan.co.uk/apoth/dipole.jpg
Pat Arnott, UNR, ATMS 749
Dipole in Abstract Fractal Art
From: http://www.raygirvan.co.uk/apoth/dipole.jpg
Pat Arnott, UNR, ATMS 749
What would the sky look like if you saw in the Uvb (290-320 nm) or near IR (700-1500 nm) instead of the visible (400-700 nm)?
Pat Arnott, UNR, ATMS 749
Rayleigh Scattering: Photon Directions
From: http://www.srrb.noaa.gov/highlights/redsky/page3.html
Pat Arnott, UNR, ATMS 749
Whitening of the horizon: Rayleigh Scattering followed by Rayleigh Extinction
From: http://www.m-why.com/archives/2005/03/
Pat Arnott, UNR, ATMS 749
Rayleigh Scattering (light scattering by air as dipole radiation)
σs = 8π 3(mr2 −1)2
3λ 4N26+3δ6−7δ
(m r − 1) x 108 = 8,342.54 + 2,406,147
(130 −1 / λ2 ) +
15,998(38.9 −1 / λ2 )
Dry air, 15 C, 101325 Pa, 0.045% CO2 by volume, vacuum λ in microns, (Birch, Metrologia, 1994, 31, 315).
From http://www.kayelaby.npl.co.uk/general_physics/2_5/2_5_7.html.
From Liou pg 93. is the molecular anisotropy parameter as the polarizability is really a tensor. The refractive index relationship is in relation to the polarizability of air. = 0.035 for air.
mr(P,t) − 1 = (mr − 1) x P[1 + P(60.1 - 0.972t) x 10-10]96 095.43(1 + 0.003 661t)
Dry air, t in Celcius, P in Pascal, 0.045% CO2 by volume, Birch, Metrologia, 1994, 31, 315).
From http://www.kayelaby.npl.co.uk/general_physics/2_5/2_5_7.html.
N= PkbT
Number concentration of air molecules.
βsca1
Mm⎛⎝⎜
⎞⎠⎟
= σ scm2
molecule
⎛
⎝⎜⎞
⎠⎟Nmolecules
cm3
⎛⎝⎜
⎞⎠⎟
108 cm
Mm⎛⎝⎜
⎞⎠⎟
Pat Arnott, UNR, ATMS 749
Dry Air Refractive Index
Pat Arnott, UNR, ATMS 749
Rayleigh Scattering (light scattering by air as dipole radiation)
Pat Arnott, UNR, ATMS 749
Rayleigh Scattering (light scattering by air as dipole radiation)
Pat Arnott, UNR, ATMS 749
Rayleigh Scattering (light scattering by air as dipole radiation)
42.3% of Total Energy, TOA
Pat Arnott, UNR, ATMS 749
Rayleigh Scattering (light scattering by air as dipole radiation)
1.5% of Total Energy, TOA
Pat Arnott, UNR, ATMS 749
Rayleigh Scattering (light scattering by air as dipole radiation)
6.3% of Total Energy, TOA
Pat Arnott, UNR, ATMS 749
Rayleigh Scattering (light scattering by air as dipole radiation)
0.5% of Total Energy, TOA
Pat Arnott, UNR, ATMS 749
Rayleigh Scattering In Perspective Relative to Absorption
Pat Arnott, UNR, ATMS 749
Angular Dependence of Rayleigh Scattering (dipole)
Horizontal E-field Vertical E-fieldDipoles don’t radiate in the direction they are undergoing linear ocsillation.
From http://www.sparknotes.com/physics/optics/phenom/section3.rhtml
From:http://qels.com/theory/rayleighscattering/mass.cfmhttp://www.bo.astro.it/sait/spigolature/spigo402base.html
Pat Arnott, UNR, ATMS 749
Rayleigh Scattering Intensity as a function of Scattering Angle.
From: http://www.jenkinsdisplays.com/led_bulbs/rayleigh_scattering.html
I0
Isca()
N scatterers / volume
Isca()=I0NσsR2
P()4π
P()=34 1+cos2()⎛
⎝⎜⎜
⎞
⎠⎟⎟
Random E-field incident, random scatterer orientation.
Pat Arnott, UNR, ATMS 749
Dipole Radiation Pattern: (Petty, Ch12).
Incident E-field vertical: Dipole charge oscillation vertical.
Incident E-field Horizontal
Irradiance Average for Random E-field: sum of the polarized patterns / 2.
= incident direction
Pat Arnott, UNR, ATMS 749
UV thoughts from http://uvb.nrel.colostate.edu/UVB/publications/uvb_primer.pdf
Pat Arnott, UNR, ATMS 749
UV thoughts from http://uvb.nrel.colostate.edu/UVB/publications/uvb_primer.pdf
Pat Arnott, UNR, ATMS 749
UV thoughts from http://uvb.nrel.colostate.edu/UVB/publications/uvb_primer.pdf
Pat Arnott, UNR, ATMS 749
UV thoughts from http://uvb.nrel.colostate.edu/UVB/publications/uvb_primer.pdf
Diffey action spectra: Damage spectra for sun-burn:305 nm, rule of thumb, ‘worst’ UV wavelength.
