Quantitative Assessment of Contrail and Anthropogenic Aerosol Radiative Effects and Their Implication to Meteorological Phenomena in the Mediterranean Basin

We quantitatively evaluated the seasonal average of the radiative effects, either at the top of the atmosphere (TOA) and at surface (SFC), and the heating rate (HR) of the anthropogenic aerosol emissions coupled with aircraft contrails, for different observational sites situated in three large metropolitan areas densely populated (> 4 millions) in the Mediterranean basin which has been identified as one of the climate hotspot regions. The evaluation is based on the use of lidar measurements of aerosol and cloud properties as input for the Fu-Liou-Gu Radiative Transfer Model (RTM). Previous papers have shown that the FLG radiative transfer model can be adapted and used to evaluate the radiative impact of aerosol and clouds along the observed vertical column if lidar extinction atmospheric profiles are used as input into the model. A quantification of the uncertainty due to the applied data processing (e.g. smoothing) has been also provided. The three identified metropolitan areas are close to large airports and subject to anthropogenic aerosol emissions especially from ship exhaust and nearby industrial areas. The first observation site is situated at Universitat Polytechnica di Catalunya in Barcelona, Spain while the second site is located at Consiglio Nazionale delle Ricerche (CNR), ISAC, Rome and the latter in Athens. The main objective of the analysis is to assess how much those anthropogenic effects impact the atmospheric column thermodynamics that in turn is linked to meteorological events. The analysis was carried out for different seasons to detect any related cycle. The results obtained with the RTM have been also validated using surface based solar irradiance measurements. Comparison with the LW and SW fluxes provided by ERA5 reanalysis will be used to test the capability of the reanalysis to properly quantify the impact of contrails on the radiative budget. The presented analysis may be considered as a pilot study to extend at other lidar station operating in the Mediterranean basin in the frame of MPLNET and ACTRIS programs and close to megacities.