Aerosol Characterization with Long-Term AERONET Sun-Photometer Measurements in the Naples Mediterranean Area

Abstract

We report on the characterization of columnar aerosol optical and microphysical properties in the Naples Mediterranean area over a period of five years by the ground-based sun–sky–lunar photometer operating at our observational station in the frame of the AERONET network. Statistical and climatological analyses of daily mean values of aerosol optical depth at 440 nm (AOD440) and Ångström exponent at 440/870 nm (α440/870) allowed for highlighting their typical seasonal behavior. In particular, we observe higher mean values of the AOD440 during summer or spring, which are consistent with an increased frequency of both Saharan dust transport events and biomass burning episodes affecting the measurement area in these periods of the year. Conversely, α440/870 does not show any typical seasonal trend. In order to gain information on the different aerosol contributions along the atmospheric column, the frequency distributions of AOD440 and α440/870 were analyzed and fitted by a superposition of Gaussian functions. The most populated modes are centered at α440/870 = 1.26 ± 0.07 and AOD440 = 0.16 ± 0.01. These values are associated with continental polluted aerosol mixed with sea salt aerosol and correspond to the background conditions typically observed in clear atmospheric conditions. Daily size distributions averaged over each month highlight that the fine aerosol component always prevails over the coarse fraction, except for the few months in which Saharan dust events are particularly frequent. Finally, the mean value of the SSA at 440 nm resulted as 0.94 ± 0.05, while the refractive index real and imaginary part were 1.47 ± 0.07 and (6.5 ± 0.2) × 10−3, respectively. These values are in agreement with those observed in other Mediterranean sites located in Southern Italy, evidencing a rather characteristic feature of the geographical region.

Variation of Aerosol Optical Properties over Cluj-Napoca, Romania, Based on 10 Years of AERONET Data and MODIS MAIAC AOD Product

“…Markowicz et al (2021), studied the climate interaction trends of aerosols distributed over Poland and their effects on incoming radiation fluxes, using a 10-year AERONET dataset [17]. Damiano et al (2022) characterized the columnar aerosol optical and microphysical properties to determine the prevailing aerosol type in the Naples Mediterranean area, using an AERONET dataset from a 5-year period [18]. AERONET and satellite datasets for a period of 16 years were also used by researchers to determine the annual variability of aerosol intrusion episodes in Morocco and the location's susceptibility to desert dust transport on a seasonal basis [19].…”

Variation of Aerosol Optical Properties and Trends over Cluj-Napoca, Romania, Based on 10 Years of AERONET Data and Satellite-Based Observations

“…Markowicz et al (2021), studied the climate interaction trends of aerosols distributed over Poland and their effects on incoming radiation fluxes, using a 10-year AERONET dataset [17]. Damiano et al (2022), characterized the columnar aerosol optical and microphysical properties to determine the prevailing aerosol type in the Naples Mediterranean area, using an AERONET dataset from a 5-year period [18]. AERONET and satellite datasets for a period of 16 years were also used by researchers to determine the annual variability of aerosol intrusions episodes in Morocco, and the location's susceptibility to desert dust transport on a seasonal basis [19].…”

Atmospheric Processes over the Broader Mediterranean Region: Effect of the El Niño–Southern Oscillation?

“…The W-ICARB campaign [102] observed that a combination of different characteristics (sea and land, meteorology, air pollution, aerosol-mixing processes, e.g., coagulation, humidification) led to mean TAOD 500 and AE 470-870 values as high as 0.39 and 1.27, respectively. In the Naples area, Italy, Damiano et al [103] A last investigation concerns the type of aerosols present in the atmosphere of the Mediterranean in the period of the study. To categorise aerosols into groups, several researchers have developed varying ranges for the TAOD 550 and AE 470-870 values, e.g., [97,[104][105][106][107][108][109][110].…”