Observation of Seasonal Variations with the MINOS Far Detector

An observation of seasonal variations in underground muon rate, $R_{\mu}$, has been performed at Soudan, MN, by the MINOS Far Detector. The four percent fluctuation seen over three years was highly correlated to the temperature variations of the upper atmosphere. The coefficient relating variations in temperature to variations in muon rate was found to be: $\alpha_T = (T/R_{\mu})(\partial R_{\mu}/ \partial T) = 0.87 \pm 0.03$, which is near the expectation of 0.91.