Characterization of Saharan dust layers over Naples (Italy) during 2000–2003 EARLINET project

Abstract

Vertically resolved observations of dust optical properties were carried out at the EARLINET station of Naples (southern Italy, 40.838° N, 14.183° E, 118m above sea level) from May 2000 to August 2003. 45 outbreaks with a mean temporal length of about 4days were observed, 40% of which were characterized by dust plume intrusion into the Planetary Boundary Layer.The mean values of the altitude of base, top and of the thickness of the dust plume were derived. Dust optical properties were studied along the vertical profile in terms of statistical and climatological analysis of aerosol backscatter, extinction and lidar ratio measured inside the dust layer. Mean values of backscattering and extinction coefficients of (1.2±0.1)10−6m−1sr−1 and (0.61±0.06)10−4m−1, respectively, were obtained in the whole observation period, while the mean value of LR at 351nm resulted to be 47±3sr. Mean values of dust concentration and dust fluxes were also estimated. The highest values of concentration have been observed on spring and summer months resulting of (150±60)μg·m−3 and (80±30)μg·m-3, and mean dust fluxes were (0.8±0.4)·10−3gm−2s−1 and (1.6±0.7)·10−3gm−2s−1, respectively.Finally, aerosol optical properties retrieved from lidar vertical profiles and sun-photometer measurement, in-situ sampling and models outcomes were used to fully examine the most intense dust outbreak observed during the whole study period.