  Cosmic rays are charged particles whose flux observed at Earth shows temporal
variations related to space weather phenomena and may be an important tool to
study them. The cosmic ray intensity recorded with ground-based detectors also
shows temporal variations arising from atmospheric variations. In the case of
muon detectors, the main atmospheric effects are related to pressure and
temperature changes. In this work, we analyze both effects using data recorded
by the Global Muon Detector Network (GMDN), consisting of four multidirectional
muon detectors at different locations, in the period between 2007 and 2016. For
each GMDN directional channel, we obtain coefficients that describe the
pressure and temperature effects. We then analyze how these coefficients can be
related to the geomagnetic cutoff rigidity and zenith angle associated with
cosmic-ray particles observed by each channel. In the pressure effect analysis,
we found that the observed barometric coefficients show a very clear
logarithmic correlation with the cutoff rigidity divided by the zenith angle
cosine. On the other hand, the temperature coefficients show a good logarithmic
correlation with the product of the cutoff and zenith angle cosine after adding
a term proportional to the sine of geographical latitude of the observation
site. This additional term implies that the temperature effect measured in the
northern hemisphere detectors is stronger than that observed in the southern
hemisphere. The physical origin of this term and of the good correlations found
in this analysis should be studied in detail in future works.
