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| Titel |
Ice Nuclei measurements across Europe within BACCHUS |
| VerfasserIn |
Matteo Rinaldi, Alessia Nicosia, Gianni Santachiara, Stefano Decesari, Marco Paglione, Silvia Sandrini, Stefania Gilardoni, Paolo Cristofanelli, Angela Marinoni, Paolo Bonasoni, Maria Cristina Facchini, Franco Belosi |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250139898
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| Publikation (Nr.) |
 EGU/EGU2017-3216.pdf |
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| Zusammenfassung |
| Ice in clouds is formed prevalently via heterogeneous nucleation involving aerosol particles
known as ice nucleating particles (INPs). A wide variety of measurement techniques have
been developed for detecting INPs in different activation modes. In this study, concentrations
of INPs were detected by the membrane filter technique, using a dynamic filter processing
chamber (DFPC).
Experimental campaigns were carried out in the framework of BACCHUS (FP7-603445) and
Air-Sea Lab (CNR) projects in different locations and seasons: San Pietro Capofiume (SPC),
a rural background site in the Po Valley (Italy) (winter campaign: SPC1; summer campaign:
SPC2); Mace Head (MH), a North Atlantic coastal site in Western Ireland, during August
2015, with the aim of investigating the dominant sources of INP in the North Atlantic Marine
Boundary Layer; Monte Cimone (MC) Global Atmospheric Watch (GAW) station, a high
altitude site (2165 m asl) in the Apennine Mounts facing the Po Valley (summer
campaign: MC1; winter campaign: MC2) and Capogranitola (CG) a coastal site
facing the Strait of Sicily, representative of the Mediterranean background, in April
2016.
Samples were collected using a parallel PM1 - PM10 sampling. The concentration of INP was
detected at different temperatures and supersaturations with respect to ice and water
(Santachiara et al., 2010). Measurements with the DFPC below water saturation (Sw< 1) are
considered representative of deposition nucleation, while above water saturation (Sw ≥ 1) of
deposition and condensation-freezing. In detail, measurements were carried out at
-22∘C (MH and CG) and -18∘C (MH, MC and CG), with Sw = 0.96 and Sw =
1.02.
The lower average concentration in the PM10 fraction was measured at MH (10 m−3) and the
highest at SPC (310 m−3, during SPC1). Comparison of INP in the PM1 and PM10 size
ranges shows the importance of measuring the freezing activity of particles larger than one
micrometer (Mason et al., 2016).
Saharan dust transport episodes were observed during the campaigns SPC2 and MC1. These
episodes are characterized by increased INP concentration in the PM10 size range,
particularly at Sw=1.02, and enhanced total super-micrometer particle concentration.
However, observations show a decrease of the activated fraction during these events. This
could depend on aging processes during long range transport of mineral dust, e.g. coating
with sulphate, sea salt, etc. (Levin et al., 2005).
Levin, Z., et al (2005) J. Geophys. Res., D20202.
Mason, R.H., et al (2016) Atmos. Chem. Phys., 16, 1637-1651.
Santachiara, G., et al (2010) Atmospheric Research 96, 266-272. |
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