Transmissivity of the atmosphere

Figure 4. Transmission of the atmosphere containing aerosols at 0% humidity, normalised to that of an aerosol-free atmosphere (from figure 7 of Erlick and Frederick 1998).

Figure 7 Transmission of the atmosphere containing a polluted stratus cloud with a varying amount of soot inclusion and disolved absorbers, normalised to clean cloudless conditions. Here f is the soot volume fraction in the cloud drops (from figure 7 of Erlick et al.l998)...

First assume that the clouds and the atmosphere act as translucent bodies absorbing or blocking the radiation coming from the sun and calculate their transmissivity (x) accordingly. For example, let us calculate the transmissivity of the atmosphere on a clear day with no clouds. Since there are no clouds the radiation reaching the earth s surface is 100%(from sun) - 16% (absorbed by atmosphere) - 6% (reflected by atmosphere). 

The view factors for each gap must be multiplied by the transmissivity of the atmosphere to get the actual view factors from the sun to the solar panel assuming the clouds are completely opaque. 

The HITRAN Molecular Spectroscopy Database (References 1 and 2) is a compilation of wavenumbers and intensities of more than 1.7 million spectral lines of atmospheric constituents. It is a valuable resource for calculating transmission of the atmosphere, radiative energy transfer, and other phenomena. The graph below, which was supplied by Walter J. Lafferty (Reference 3), gives the... 

Fig. 2.6 Forman phase correction method. The real and imaginary part of the spectrum corresponding to the transmission of the atmosphere from 0 to 42 cm has been distorted (top-left) with a linear phase error (top-right). The measured interferogram is not symmetric anymore (centre-left). After extracting the convolution kernel (centre-right) and applying the correction method 5 times, the interferogram symmetry is improved (bottom-left). Fourier transforming the corrected interferogram, the spectrum is recovered (bottom-right) and is real...

The key to the value of balloon-borne observations for infrared astronomy lies in the behavior of atmospheric absorption by triatomic and diatomic molecules and by methane. Figure 1 shows the transmission of the atmosphere from 100 to 50 microns at 4 altitudes, (Traub, W. A., and Stier, M. T., 1976, Applied Optics, 15, 364) The transmission is given for an air mass of two. The altitudes are 4.2 kilometers (13800 ) the height of the Mauna Kea Observatory, 14 kilometers (46,000 ) the approximate altitude of aircraft flights, 28 kilometers (92,000 ) the lower end of the... 

The transmissivity of the atmosphere is determined from Eq. (3.42). This requires a value, X for the path length from the surface of the fireball to the target, as shown in Figure 3.27. This path length is from the surfiice of the fireball to the receptor and is equal to the hypotenuse minus the radius of the BLEVE fireball. 

Here B is the world average burden of anthropogenic sulfate aerosol in a column of air, in grams per square meter. The optical depth is then used in the Beer Law (which describes the transmission of light through the entire vertical column of the atmosphere). The law yields I/Iq = where I is the intensity of transmitted radiation, Iq is the incident intensity outside the atmosphere and e is the base of natural logarithms. In the simplest case, where the optical depth is much less than 1, (5 is the fraction of light lost from the solar beam because of... 

Figure 5.11 A constant velocity Mossbauer experiment reveals the kinetics of the denitridation of an iron nitride in different gases at 525 K. The negative part of the time scale gives the transmission of the most intense peak of the nitride at time zero the gas atmosphere is changed to the desired gas. Denitridation occurs relatively fast in H2, but is retarded by CO, whereas the nitride is stable in an inert gas such as helium (from Hummel etal. [33]).

The transmission of the detonation figure for the complete cartridge is 4-7 cm. Pobedit P-8 is tested not only in a steel mortar in a gallery, but also suspended free in methane atmosphere and in the presence of coal-dust. 

Instrumentation developments in the 1920 s and 30 s led to a rapid expansion of spectroscopic methods in the laboratory (28, 34-39). These included further penetration into the infrared regime and some applications to infrared transmission in the atmosphere. Additional equipment was developed during World War II as a result of military requirements. This period was a fruitful one for the science of spectroscopy, and saw the first applications of infrared equipment as gas measurement tools (40-41) and as routine process controllers (42). 

During the process of transmission through the atmosphere a change in the chemical composition of the dust takes place, basically as a result of meteorologically induced chemical and physical processes. 

In this volume, the first area to be explored is the photochemistry of processes at the semiconductor/solution interface. The treatment is necessarily quantal and illustrates principles discussed in Chapter 9. Applied to the photosplitting of water, this material has great relevance to future developments in theproduction, transmission, and storage of energy without adding further to the C02 burden of the atmosphere. 

Readily Carbonizable Substances Transfer 1.00 + 0.01 g of finely powdered Citric Acid to a 150-mm x 18-mm (od) tube previously rinsed with 10 mL of 98% sulfuric acid at 90° or used exclusively for this test. Add 10 + 0.1 mL of 98% sulfuric acid, carefully agitate the tube until solution is complete, and immerse the tube in a water bath at 90° + 1° for 1 h. Occasionally remove the tube from the water bath and carefully agitate it to ensure that the Citric Acid is dissolved and gaseous decomposition products are allowed to escape to the atmosphere. Cool the tube to ambient temperature, carefully shake the tube to ensure that all gases are removed, and using an adequate spectrophotometer, measure the absorbance and transmission of the solution at 470 nm in a 1-cm cell. The absorbance does not exceed 0.52, and the transmission is equal to or exceeds 30%. 

No transmission of the internal explosion into the surrounding atmosphere shall occur at all 30 tests... 

Because of the wide transmission range and low phonon energies of fluoride glasses, the observation of numerous rare-earth laser lines is possible at wavelengths beyond 2 fim, where the transmission of silica fibers is extremely poor. Laser sources around 2 /jm are of special interest because they belong, not only to the eye-safe spectral domain, but also to an optical transparency window of the atmosphere. Two fluoride glass fiber lasers have been demonstrated in that region. First, a Ho3+ laser with the 5I7 -> 5I8 transition at 2.024 /on which delivers 250 mW with 60%... 

Leung, Colussi and Hoffmann have used isotopic analysis in an attempt to constrain the amount of sulfate that could be produced by Crutzen s mechanism [129,130]. The first study retrieved the concentration profiles of OC S and OC S from infrared transmission spectra of the atmosphere recorded by the NASA MkIV balloon-borne interferometer. They derived an enrichment factor of 73.8 zb 8.67oo defined such that photolytically generated sulfur would be enriched in An isotopic budget based on this result shows that OCS photolysis cannot be a significant source of sulfate aerosol, since the enrichments of OCS, sulfuric acid aerosol and SO2 are known to be small [131]. A later laboratory study by the same group came to the conclusion that stratospheric photolysis results in an enrichment of 67 zb 77oo. 

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