Thirteen Years' Measurements of Solar Radiation

Abstract

IN a paper entitled “Valeurs Pyrheliométriques et les sommes d'insolation à Varsovie,” Dr. Ladislas Gorczynski discusses the measurements which he has made at Warsaw with actinometers and pyrhelio-meters during the thirteen years 1901–1913. The results are to some extent of a provisional character, and they have been published chiefly with a view of assisting the Commission on Solar Radiation in its inquiry into the exceptional character of the latter half of the year 1912. During that period the intensity of solar radiation appeared generally to be considerably below the values previously found; the decrease was indeed so marked that it could be detected in the records from the Campbell-Stokes instrument which is designed primarily for the registration of duration of sunshine. The diminution has been attributed to the presence in the atmosphere of an exceptional amount of fine dust arising from the volcanic eruption of Katmai, in Alaska, at the end of June, 1912.