The dependence of the muon flux on the atmospheric parameters (pressure and temperature) is a well-known effect since long time ago. We have correlated the muon flux recorded by the electromagnetic detector of EAS-TOP with the atmospheric temperature (up to few hPa level) monitored by the radio-soundings of the ITAV—Aeronautica Militare at Pratica di Mare (Rome). A significant effect has
been observed when the muon flux is correlated with the atmospheric temperature in the region 50–200 hPa, as expected, since this is the region where the mesons of
first generation are produced. The technique has been applied to two short periods of strong temperature variations in the low stratosphere, showing that the temporal pattern of the temperature is fairly well reproduced by the variations of the muon flux. The main results of this analysis are presented
