Atmospheric Monitoring at the Pierre Auger Observatory – Status and Update

Calorimetric measurements of extensive air showers are performed with the fluorescence detector of the Pierre Auger Observatory. To correct these measurements for the effects introduced by atmospheric fluctuations, the Observatory operates several instruments to record atmospheric conditions across and above the detector site. New developments have been made in the study of the aerosol optical depth, the aerosol phase function and cloud identification. Also, for cosmic ray events meeting certain criteria, a rapid monitoring program has been developed to improve the accuracy of the reconstruction. We present an updated overview of performed measurements and their application to air shower reconstruction.