The Rates of Penetrating Showers at Sea Level

Abstract

The times of arrival of 17 665 local and 2526 extensive penetrating showers have been recorded. The showers penetrated various thicknesses of lead from 17.5 cm to 97.5 cm. A variation of the rate of local showers with solar time which is correlated with the small diurnal pressure variations appears to be statistically established. This variation seems to have a much larger barometric coefficient than that derived from the large pressure changes associated with the weather. No significant variation of the rate of local showers with sidereal time was found. Possible variations of the rates of penetrating extensive showers with solar and with sidereal time are discussed.