Effetti atmosferici sullo spettro dei raggi cosmici con il detector di superficie dell'osservatorio Pierre Auger

The weather effects on the extensive air showers development, induced in atmo- sphere by high energetic cosmic rays, will be studied using the data recorded by the Surface Detector of the Pierre Auger Observatory. The weather changes, as will be discussed, affect the measurement of the signal and then the recon- struction of the energy, introducing a systematic uncertainty. Using a weather correction model, it is possible to remove this systematic uncertainty, obtaining an energy measurements independent from the atmospheric conditions. The goals of the present work is to implement this weather correction model on the measured data, studying the effects on the energy calibration curve and on the energy spectrum, in order to improve the flux measurements of high energy cosmic rays.