Galactic cosmic rays flux and geomagnetic activity coupling with cloud covering in Abastumani

Abstract

The analysis of long-term observations in Abastumani (41.75° N, 42.82° E) revealed differences in the seasonal variations of Galactic Cosmic Rays (GCRs) flux and geomagnetic activities at cloudless days and cloudless nights. Particularly, in summer, the inter-annual distributions of the planetary geomagnetic Ap index and Sudden Storm Commencement (SSC) exhibited minima for cloudless days and maxima for cloudless nights, where GCR flux showed deep minimum. This feature in the case of SSC was demonstrated for the first time. The long-term trends of Ap index during summer time also revealed various meanings for cloudless day and night. These results can be regarded as the effect of cosmic factors on cloud covering in Abastumani, which in turn may have an influence on climatic variations.