The World aerosol Optical depth Research and Calibration Center (WORCC), Quality assurance and quality control of GAW-PFR AOD measurements

Abstract. The World Optical Depth Research Calibration Center (WORCC) is a section within the World Radiation Center at Physikalisches-Meteorologisches Observatorium (PMOD/WRC), Davos, Switzerland, established after the recommendations of WMO for calibration of AOD related sun-photometers. WORCC is mandated to develop new methods for instrument calibration, to initiate homogenization activities among different AOD networks and to run a network (GAW-PFR) of sun-photometers. In this work we describe: the calibration hierarchy and methods used under WORCC and the basic procedures, test and processing techniques in order to ensure the quality assurance and quality control of the AOD retrieved data.