Marine aerosol particles and infrared transmission

Abstract : The propagation of infrared radiation close to the ocean surface is controlled by three effects: (1) extinction (absorption and scattering) by aerosol particles, (2) extinction by molecules, and (3) refraction. Molecular extinction can be predicted with fair accuracy by transmission codes such as MODTRAN, and refraction can often be ignored along paths shorter than 10 km. Hence, by making continuous measurements of infrared transmission, a continuous record of aerosol transmission after removing the molecular transmission should be obtainable. This paper shows that this is indeed the case for mid- and longwave infrared transmission measured several meters above San Diego Bay.