Table 141 



ABSORPTION OF RADIATION BY CARBON DIOXIDE 



427 



A. — Mean percentage absorption by carbon dioxide (C0 2 ) from parallel beams of vari- 

 ous wave-length intervals, under laboratory conditions of pressure and temperature. 1 



CO a path 

 length * 



cm. 



0.004 



0.05 



0.23 



0.68 



1.00 



1.58 



4 



20 



25 



100 



400 



* Reduced to normal pressure and temperature. 



Observers: M— Martin, P., and Barker, E., Phys. Rev., vol. 41, p. 176, 1932. 



R— Rubens, H., and Ladenberg, E., Verh. Phys. Ges., vol. 7, p. 170, 1905. 



Data on the variation with pressure and temperature of absorption by carbon dioxide 

 is inconclusive. Brooks a reports that Bruinenburg 3 and Moller 4 assume the variation 

 with pressure to be proportional to p° ", while Elsasser 5 uses the factor p 0,5 . Variation 

 with temperature (°K.) is usually assumed to be small, approximately proportional to 



■y-0.25 



Carbon dioxide also has an absorption band in the region of 4.3 microns, but this band 

 is not generally considered to be meteorologically significant. The mean absorption in 

 the region 4.0-4.5/ti is about 67 percent for 1 centimeter of CO2. 



B. — Absorption by CO2 from parallel beam of equal light intensity from 14 to 16 

 microns, calculated from quantum mechanics for stratospheric conditions (p = 203 mb., 

 7 = 218 °K.). 8 -' 



C0 2 path 

 length * 



cm. 



0.004 

 .05 

 1. 

 4. 

 20. 



* Reduced to 1013.25 mb. and °C. 



t For a concentration of 3.0 X 10 -4 parts of carbon dioxide by volume. Since in atmospheric prob- 

 lems the rlux of radiation is diffuse, rather than in parallel beams, the figures in the first column were 

 divided by 1.66 before computing the corresponding air thickness in the second column. 6 



1 Callendar, G. S., Quart. Journ. Roy. Meteorol. Soc, vol. 67, p. 263, 1941. 



2 Brooks, D. L., Measurements of atmospheric radiation applied to the heat transfer by infrared 

 radiation in the free atmosphere, Sc. D. dissertation, M. I. T., 1948. 



3 Bruinenburg, A., Koninlijk Ned. Met. Inst, de Bilt, ser. B, Deel I, 1946. 



4 Moller, F., Meteorol. Zeitschr., vol. 61, p. 37, 1944. 



s Elsasser, W. M., Harvard Meteorol. Series, No. 6, 1942. 

 « Kaplan, L. D., Journ. Chem. Phys., vol. 15, p. 809, 1947. 

 7 Kaplan, L. D., private communication, July 1949. 



SMITHSONIAN METEOROLOGICAL TABLES 



