Understanding the Effect of Atmospheric Density on the Cosmic Ray Flux Variations at the Earth Surface

We report in this letter for the first time the numerical simulations of muon and neutron flux variations at the surface of the earth with varying air densities in the troposphere and stratosphere. The simulated neutron and muon flux variations are in very good agreement with the measured neutron flux variation in Oulu and the muon flux variation in Atlanta. We conclude from this study that the stratosphere air density variation dominates the effects on the muon flux changes while the density variation in troposphere mainly influences the neutron count variation. These results pave a new path for systematically studying the global temperature evolution using worldwide cosmic ray data.