Atmospheric transmittance

Straw, L. L., Motteler, H. E Benson, R.G., Hannon S.Eand De Souza-Machado, S. (1998) Fast computation of monochromatic infrared atmospheric transmittances using compressed look-up tables, J Quant. Spectrosc. Radial. Transfer, 59,481-493... 

Edwards, D. P. (1992) GENLN2 A general line-by-line atmospheric transmittance and radiance model. Version 3.0 description and users guide, Report NCAR/TN-367+STR, Natl.CenLfor Atmos.Res., Boulder, Colo. 

In the absence of clouds, S can be related to the solar constant (1366 W m-2 Sc) and the atmospheric transmittance x (the fraction of sunlight transmitted when the sun is directly overhead), which ranges from 0.5 under hazy conditions at sea level to 0.8 for clear skies at higher elevations ... 

Figure 26 Calculated relation between albedo and the number concentration of eloud droplets. The sloping line shows the relation between the albedo (at various levels of the atmosphere and globally) as a function of an increase in number concentration of cloud-droplets, A cd- The four ordinates show the perturbation in eloud-top albedo (left axis), TOA albedo above marine stratus (first right axis), global-mean albedo (second right axis), and global-mean eloud radiative forcing (far right axis). The fractional atmospheric transmittance of short-wave radiation above the eloud layer was taken as 76%. The dotted line indieates the perturbations resulting from a 30% inerease in Ned (Charlson et al., 1992) (reproduced by permission of American Association for the Advancement of Seience from Science,...

To derive the parameters r, the atmospheric transmittance, and L, the path radiance, linear regression analyses were performed on radiances from the satellite measurements, L, and radiances derived from shipboard measurements of temperature, L, versus elapsed distance, X, along selected parts of the track. These track segments were selected nearest in time to the satellite overpass and where temperature gradients were large enough to minimize the relative errors due to satellite-measured thermal noise and the lower AVHRR temperature resolution of 0.5 °C in the 8-bit data from Redwood City. 

Figure 2. Atmospheric transmittance at Climax, Colo, (altitude, 11,190 feet), and determination of total ozone above observing station...

Eor the EPA evaluations, it is to be assumed that the hazardous intensity of thermal radiation q would be 5 kilowatts per square meter (0.44 BTU/sec/fE) and that the duration of exposure would be 40 seconds. Thus, if the exposed person(s) retreated from the pool fire or took refuge in the shadow of a structure, the hazard of thermal-radiation exposure could be reduced significantly. It was also assumed that the fraction of heat e that would be radiated from a pool fire would be 0.4 and that the atmospheric transmittivity x would be 1.0. Values for e, x, and q are available in the literature [26, 27, 28]. 

In order to obtain an estimate of the atmospheric transmittance as a result of absorption by O2... 

Fig. 3.9 Atmospheric transmittance at the solar zenith angle 45°. Ta Absorption by ozone, Tn, Rayleigh scattering by molecules, Tpi Mie scattering by particles,...

The functional derivatives with respect to temperature are calculated assuming that the temperature dependence of the atmospheric transmittance is weak relative to that of the Planck function so that K can be approximated as... 

These are applicable to the 10 cm spectral resolution measurements obtained by the Thermal Emission Spectrometer carried on the Mars Global Surveyor spacecraft (Christensen et al., 1998), and points on both sides of the 15 pun CO2 band are included. Rapid calculation of atmospheric transmittances is required for temperature retrieval from a large volume of spacecraftmeasurements, and the A -distribution method is used (Goody Yung, 1989). 

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