Due to the high vulnerability to climate change and temperature rise predictions higher than the global average, Mediterranean basin and Southern Europe are key areas in understanding long-term regional climate change. They are frequently interested by the presence of desert dust aerosol transported from North Africa which plays an important role in climate and environmental system, by affecting the radiation budget of the atmosphere and the surface albedo of Alpine snow and glaciers, also affecting their melting rate. Mt. Cimone (2165 m a.s.l., 44°11'N, 10°42'E) is the highest peak of the Italian northern Apennines and represents one of the first mountain ridges that Saharan air masses encounter during their northward displacement towards Europe and Alpine ranges. Dust transport events (DTEs) have been identified since 2002 at the CNR baseline global GAW station of Mt. Cimone (MTC) when the atmospheric concentration of coarse particle (1 ?m <= Dp<= 20 ?m) significantly increased with air-masses coming from North Africa as deduced by back-trajectory simulations. The FLEXTRA three-dimensional 6-day back-trajectories analysis also permitted to make a statistical climatology of the optical and microphysical properties of the aerosol according to the origin of the air masses. A number of 380 DTEs were pointed out, corresponding to 15% of the investigated period at MTC. During those days the coarse particle number was 685% higher than with respect to rest of the time. It could be noted that 65% of DTEs occurs in spring and summer. With the aim to investigate the impact of dust transport on aerosol optical properties at MTC and to study their seasonal variability, the absorption and scattering coefficients during DTEs have been calculated on a seasonal basis. Both scattering and absorption coefficients clearly showed an increase of the optical capability in presence of dust, while the total aerosol particle number concentration decreased (Table 1). It has also been observed a seasonal variability of all parameters with a summer maximum and a winter minimum.
Optical properties of atmospheric Saharan dust particles at the Mount Cimone GAW Global Station, Italy (2165 m a.s.l.)
L Bourcier;A Marinoni;P Cristofanelli;R Duchi;D Putero;TC Landi;F Calzolari;M Busetto;P Bonasoni
2013
Abstract
Due to the high vulnerability to climate change and temperature rise predictions higher than the global average, Mediterranean basin and Southern Europe are key areas in understanding long-term regional climate change. They are frequently interested by the presence of desert dust aerosol transported from North Africa which plays an important role in climate and environmental system, by affecting the radiation budget of the atmosphere and the surface albedo of Alpine snow and glaciers, also affecting their melting rate. Mt. Cimone (2165 m a.s.l., 44°11'N, 10°42'E) is the highest peak of the Italian northern Apennines and represents one of the first mountain ridges that Saharan air masses encounter during their northward displacement towards Europe and Alpine ranges. Dust transport events (DTEs) have been identified since 2002 at the CNR baseline global GAW station of Mt. Cimone (MTC) when the atmospheric concentration of coarse particle (1 ?m <= Dp<= 20 ?m) significantly increased with air-masses coming from North Africa as deduced by back-trajectory simulations. The FLEXTRA three-dimensional 6-day back-trajectories analysis also permitted to make a statistical climatology of the optical and microphysical properties of the aerosol according to the origin of the air masses. A number of 380 DTEs were pointed out, corresponding to 15% of the investigated period at MTC. During those days the coarse particle number was 685% higher than with respect to rest of the time. It could be noted that 65% of DTEs occurs in spring and summer. With the aim to investigate the impact of dust transport on aerosol optical properties at MTC and to study their seasonal variability, the absorption and scattering coefficients during DTEs have been calculated on a seasonal basis. Both scattering and absorption coefficients clearly showed an increase of the optical capability in presence of dust, while the total aerosol particle number concentration decreased (Table 1). It has also been observed a seasonal variability of all parameters with a summer maximum and a winter minimum.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
