Date of Award

Fall 12-18-2013

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Physics and Astronomy

First Advisor

Dr. Xiaochun He

Second Advisor

Dr. Unil Perera

Third Advisor

Dr. Murad Sarsour

Fourth Advisor

Dr. Douglas Gies


Since 1950's there has been a growing interest of understanding the effects of cosmic ray radiation on the increase in average global temperature. Recent studies showed that galactic cosmic rays play a significant role in the formation of low cloud coverage and its consequent impact on the global temperature variation of the earth. A long-term measurement of the cosmic ray flux distribution at the surface of the earth has been established at Georgia State University. The current effort is focused on understanding the correlations between the cosmic ray particle flux distribution and the atmospheric and space weather measurements.

In order to understand the observed atmospheric effects on cosmic ray flux, numerical simulations of cosmic muon and neutron flux variations at the surface of the earth have been carried out with varying air densities in the troposphere and stratosphere based on the Geant4 package. The simulation results show a remarkably good agreement with observations. The simulation results also show that the stratosphere air density variation dominates the effects on the muon flux changes while the density variation in the troposphere mainly influences the neutron count variation. This suggests that the long-term variation of muon flux could possibly direct us to a new path to understand the global climate warming trend.