An automatic planetary boundary layer height detection with a compact aerosol UV lidar

Urbanized cities in the world are exposed to atmospheric pollution events. To understand the chemical and physical processes it is necessary to describe correctly the Planetary Boundary Layer (PBL) dynamics and height evolution. For these proposals, a compact and rugged eye safe UV Lidar, the EZLIDAR(TM), was developed together by CEA/LMD and LEOSPHERE (France) to study and investigate structural and optical properties of clouds and aerosols and PBL time evolution. A new 2D method of PBL detection, developed by Leosphere and based on image processing, is working on a large set of temporal profiles, typically 6 to 24 hours. It allows the use of the temporal correlation between the profiles and the integration of atmospheric parameters about PBL evolution in the detection algorithms. This method, based on the gradient, is using a unique automatic threshold algorithm that will adapt to any atmospheric conditions. No specific parametrisation is required before measurements and the final result is more robust than a profile per profile method. We validated our algorithm during the two campaigns of the ICOS (Integrated Carbon Observation System) project. These campaigns took place at Trainou (France) on October 2008 and at Mace Head (Ireland) on June 2009 under very different and complicated atmospheric situations, with all different meteorological conditions (frequent showers, windy situations, no significant inversion layer). Furthermore, this algorithm is able to detect accurately clouds and rain episode. ? 2010 Copyright SPIE - The International Society for Optical Engineering.