Infra-red absorption by carbon dioxide, with special reference to atmospheric radiation


  • G. S. Callendar


Recent additions to our knowledge of the structure of the water vapour spectrum (Elsasser 1940), and the atmospheric transmission of infra-red radiation (Adel 1939), have tended to emphasise the importance of atmospheric radiation as a fundamental factor in meteorological processes.

Normally the greater part of this radiation comes from the large quantities of water vapour present in the air, but there are certain important regions of the atmosphere where the amount of water vapour is extremely small and where a large part of the radiation comes from the carbon dioxide always present.

It is probable that measurements of carbon dioxide absorption and radiation have been more numerous and extensive than for most other gases, but these observational data are scattered through the scientific literature of many decades and in several languages; also they are usually presented in a form which cannot be applied to atmospheric conditions and which requires much coordination and simplification before it can be used for the calculation of energy exchanges. In the following pages these measurements are reviewed and the different sets of observations are compared with the aid of a simple function which will give the absorption by any quantity of CO2 in the different wave bands.