Factors affecting the comparisons of planetary boundary layer height retrievals from CALIPSO, ECMWF and radiosondes over Thessaloniki, Greece

The aim of this study is to propose an evaluation methodology of CALIPSO retrievals of the planetary boundary layer (PBL) height using the analyses of the operational early-delivery assimilation system of the European Centre for Medium-Range Weather Forecast (ECMWF) and Radiosonde observations. The investigation is performed over Thessaloniki, Greece, for a period of almost 5 years between 2006 and 2011. Low correlations between CALIPSO and ECMWF are found when CALIPSO aerosol classification scheme reveals dust presence over Thessaloniki. When eliminating cases of dust advection, the correlation between CALIPSO and ECMWF improves considerably, reaching a value of 0.82, while the correlation between CALIPSO and radiosondes reaches 0.74. The proposed methodology for evaluation shows a good potential for future work when more stations will be considered. Taking into account the aforementioned limitations due to the presence of advected dust layers for the Mediterranean site investigated here, the CALIPSO PBL height could be considered a valuable satellite product for investigating the atmospheric boundary layer processes and for evaluating global and regional atmospheric models.