Retrieval of Particulate Exchanges over Semiarid Ecosystems Based on a Doppler Lidar Methodology

Aerosol particle fluxes have hardly been studied with lidar techniques, although they have been largely studied with in-situ instrumentation throughout the last half century. A novel stand-alone methodology for Doppler lidars was developed and applied for the determination of turbulent aerosol particle exchanges, based on the eddy covariance technique. Flux density profiles were calculated and vertical transport velocity profiles were used for the analysis of the particulate exchanges over two distinct Mediterranean dryland ecosystems. Several case studies were examined and notable upward transport velocities were observed during convective regimes and during windy conditions, related to an increase in turbulent activity. Both locations were found to be net sources of aerosol particles during the studied period, although with slightly different average behavior. Footprint analysis confirmed the representativeness of the measurements to their respective ecosystems.