Techniques of Determinig the Turbidity of the Atmosphere¹

1 Since the present paper had gone to print, the author has had opportunity to study an important paper by Dr Mircea Herovanu: Defermination des paramètres d’ Ångström par des observations actinomériques corrrantes (Geofisica pura e applicata, Vol. 44 1959/III). Evidently the method of Herovanu is fundamentally very similar to the one applied in the present paper, with the exception that Herovanu does not make the simplifying assumption that the two groups of radiation, corresponding to our λ, and λ₂, can be regarded as homogeneous. His computations then are more laborious and must be based on graphical integration. It can be shown however, that his results, with such an accuracy as the measurements are justifying, can be derived equally well, in applying equations perfectly similar to those given ;n the present paper. His investigation then furnishes a further support for the validity for practical work of the assumption as regards the the homogenety of the wavelength groups considered. I propose to considered this question more in detail in a following note.

Abstract

After a short survey I of the principles underlying the determination of the turbidity coefficient β, earlier introduced by the author as a measure of the atmospheric turbidity, a condensed summary II is given of earlier and also of more recent determinations of β. The variation of the turbidity with the time of the year, the airmass and with latitude is discussed. Finally a simple method of determining the wave length dependence of the extinction by atmospheric aerosol is outlined. The method is founded upon measurements of integral radiation values with aid of pyrheliometers and glass filters, III. Accuracy and probable error are considered, IV.

Notes

1 Since the present paper had gone to print, the author has had opportunity to study an important paper by Dr Mircea Herovanu: Defermination des paramètres d’ Ångström par des observations actinomériques corrrantes (Geofisica pura e applicata, Vol. 44 1959/III). Evidently the method of Herovanu is fundamentally very similar to the one applied in the present paper, with the exception that Herovanu does not make the simplifying assumption that the two groups of radiation, corresponding to our λ, and λ₂, can be regarded as homogeneous. His computations then are more laborious and must be based on graphical integration. It can be shown however, that his results, with such an accuracy as the measurements are justifying, can be derived equally well, in applying equations perfectly similar to those given ;n the present paper. His investigation then furnishes a further support for the validity for practical work of the assumption as regards the the homogenety of the wavelength groups considered. I propose to considered this question more in detail in a following note.