Stratospheric aerosols measurements at CEILAP, ArgentinaTwo case studies

Résumé

CEILAP lidar, located at Buenos Aires, Argentina (34.6 ºS and 58.5 ºW), was usually employed for atmospheric boundary layer, tropospheric aerosols and cirrus clouds measurements. We conducted two cases study to evaluate the potential of such lidar for lower stratospheric aerosols measurements. Two lidar profiles were processed using the appropriated software, developed at Camagüey Lidar Station. The results show clear evidence of the presence of stratospheric aerosols in the backscattering profiles above the tropopause level. Signal – noise relationship are employed as a quality control and discrimination procedure for determining the capability to retrieve stratospheric aerosols information from such measurements. One comparison between space – time coincident extinction profiles from lidar and SAGE II is conducted. AOD calculated from the lidar derived aerosols extinction profiles were compared with the AOD measured by the AERONET sun-photometer lidar operating at CEILAP. Results corroborate the lidar capabilities for such measurements, as well as the effectiveness of the processing algorithm. We also documented the advantage of using aerological sounding to derive the molecular backscattering profile, instead of using statistical density models, based on mean soundings or the standard atmosphere. The source of the stratospheric aerosols measured by the CEILAP lidar was analyzed using back-trajectories analysis. It allows explaining the agreements and disagreements of the lidar and SAGE II stratospheric aerosols extinction profiles taking into account the sources of the air masses sampled by both instruments