Low cloud anomalies at middle latitudes and their relationship to variations of galactic cosmic rays for the different states of the polar vortex

Abstract

Long-term correlations between low cloud anomalies at middle latitudes of the Northern and Southern hemispheres and fluxes of galactic cosmic rays (GCRs) are studied. It is shown that the relationship between the state of clouds and GCR fluxes on a decadal time scale is due to GCR influence on the intensity of cyclonic processes, which dependence on the state of the stratospheric polar vortex. A possible reason for the reversal of the sign of the correlation between low cloud anomalies and GCR fluxes in the early 2000s is a sharp weakening of the polar vortices in both hemispheres that altered the role of GCRs in the development of extratropical cyclogenesis.