The seasonal variations of cosmic-ray intensity and temperature of the atmosphere

Abstract

A careful examination of the upper atmospheric data for Europe and the United States indicates that the mean temperature of the upper atmosphere in spring differs from that in summer more than from that in winter. The magnitude of the second difference as defined by (1) depends on the height of the atmosphere which is considered and is a maximum at a height of about 6 km. and changes sign at heights above 12 km. (figure 1). This lag in the warming of the atmosphere in spring is found to be paralleled by a lag in the diminution of intensity of the cosmic-rays. A similar phenomenon is found in autumn. The cooling of the atmosphere as a whole is found to be less between summer and autumn than between autumn and winter, though the effect is markedly less definite than in spring. The cosmic-ray variations are found to be correlated more closely with the mean temperature of the atmosphere up to 16 km. than with the temperature near the ground. This provides additional support for the theory of Blackett that the temperature variation of penetrating cosmic-rays is related to the instability of the mesotron. The temperature coefficient of the cosmic-rays as deduced from the seasonal data is found to be 0.18 %/° C, and this is in rough agreement with the prediction of the theory.