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version: 6
# These spectra override the spectra further down the document. This is to make sure
# we have all the required spectra inlined, rather than just references to files.
wavelengths: min=360nm,max=830nm,count=16
solar irradiance at toa: 1.03699994,1.24899995,1.68400002,1.97500002,1.96800005,1.87699997,1.85399997,1.81799996,1.72300005,1.60399997,1.51600003,1.40799999,1.30900002,1.23000002,1.14199996,1.06200004
#Copy of original atmosphere description
version: 6
transmittance texture size for VZA: 256
transmittance texture size for altitude: 64
irradiance texture size for SZA: 64
irradiance texture size for altitude: 16
scattering texture size for VZA: 128 # must be even
scattering texture size for dot(view,sun): 8
scattering texture size for SZA: 32
scattering texture size for altitude: 32
eclipsed scattering texture size for relative azimuth: 32
eclipsed scattering texture size for VZA: 128
eclipsed double scattering texture size for relative azimuth: 16
eclipsed double scattering texture size for VZA: 128
eclipsed double scattering texture size for SZA: 16
eclipsed double scattering number of azimuth pairs to sample: 2
eclipsed double scattering number of elevation pairs to sample: 10
light pollution texture size for VZA: 128
light pollution texture size for altitude: 64
light pollution angular integration points: 200
transmittance integration points: 500
radial integration points: 50
angular integration points: 512
angular integration points for eclipse: 512
scattering orders: 4
Earth-Sun distance: 1.01208 AU # on 2017-08-21 at 12:12:12 UTC
Earth-Moon distance: 371925 km # on 2017-08-21 at 12:12:12 UTC
Earth radius: 6371 km # FIXME: at R=6371km and h=120km highest altitude layer appears to have some artifacts in first scattering from near horizon
atmosphere height: 120 km
wavelengths: min=360nm,max=830nm,count=16
# Data for solar irradiance were taken from
# https://www.nrel.gov/grid/solar-resource/assets/data/astmg173.zip
# which is linked to at https://www.nrel.gov/grid/solar-resource/spectra-am1.5.html
# Values are in W/(m^2*nm).
solar irradiance at TOA: 1.037,1.249,1.684,1.975,1.968,1.877,1.854,1.818,1.723,1.604,1.516,1.408,1.309,1.23,1.142,1.062
# Taken from http://gsp.humboldt.edu/olm/Courses/GSP_216/lessons/reflectance.html, in particular, the file link:
# http://gsp.humboldt.edu/olm/Courses/GSP_216/lessons/reflect.csv
# The data set chosen is that for grass.
ground albedo: 0.035,0.037,0.04,0.041,0.043,0.067,0.107,0.09,0.07,0.057,0.047,0.138,0.367,0.468,0.483,0.491
# This spectrum was taken from a measurement of a single HPS lamp and dividing the measured spectrum by its luminance.
light pollution relative radiance: 0,0,4.3e-7,1.623e-6,2.15e-6,1.114e-6,3.858e-6,0.0000241,0.0000335,0.00001331,9.5e-6,4.304e-6,3.805e-6,4.315e-6,4.956e-6,0.00003008
Scatterer "molecules": # Rayleigh scattering
{
number density: # in m^-3
```
CONST float rayleighScaleHeight=8*km;
return 3.08458e25*exp(-1/rayleighScaleHeight * altitude);
```
phase function:
```
return vec4(3./(16*PI)*(1+sqr(dotViewSun)));
```
cross section at 1 um: 0.04022 fm^2
angstrom exponent: 4
phase function type: achromatic
needs interpolation guides
}
Scatterer "aerosols": # Mie scattering
{
number density: # in m^-3
```
CONST float mieScaleHeight=1.2*km;
return 1.03333e8*exp(-1/mieScaleHeight*altitude);
```
phase function:
```
CONST float g=0.76;
CONST float g2=g*g;
CONST float k = 3/(8*PI)*(1-g2)/(2+g2);
return vec4(k * (1+sqr(dotViewSun)) / pow(1+g2 - 2*g*dotViewSun, 1.5) + 1/((1-dotViewSun)*600+0.05))*0.904;
```
cross section at 1 um: 0.042968 um^2
angstrom exponent: 0
phase function type: achromatic
}
Absorber "ozone":
{
number density:
```
CONST float totalOzoneAmount=370*dobsonUnit;
float density;
// A fit to AFGL atmospheric constituent profile. U.S. standard atmosphere 1976. (AFGL-TR-86-0110)
// Reference was taken from data supplied with libRadtran.
if(altitude < 8*km)
density = 7.2402403521159135e-6 - 1.206527437798165e-7/km * altitude;
else if(altitude < 21.5*km)
density = -0.000020590185333577628 + 3.3581504669318765e-6/km * altitude;
else if(altitude < 39*km)
density = 0.00010542813563268143 - 2.50316678731273e-6/km * altitude;
else
density = 0.04298160111157969 * exp(-0.2208669270720561/km * altitude);
density *= totalOzoneAmount;
return density;
```
# Data were taken from
# http://www.iup.uni-bremen.de/gruppen/molspec/downloads/serdyuchenkogorshelevversionjuly2013.zip
# which is linked to at
# http://www.iup.uni-bremen.de/gruppen/molspec/databases/referencespectra/o3spectra2011/index.html
# Data are for 233K. Values are in m^2/molecule.
cross section: 1.394e-26,6.052e-28,4.923e-27,2.434e-26,7.361e-26,1.831e-25,3.264e-25,4.514e-25,4.544e-25,2.861e-25,1.571e-25,7.902e-26,4.452e-26,2.781e-26,1.764e-26,5.369e-27
}
|
