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Observations of the aerosol particle number concentration in the marine boundary layer over the south-eastern Baltic Sea

Byčenkiene S., Ulevicius V., Prokopčiuk N., Jasinevičiene D.

Oceanologia

2013

No. 55 (3)

573--598

Continuous measurements of the aerosol particle number concentration (PNC) in the size range from 4.5 nm to 2 µm were performed at the Preila marine background site during 2008–2009. The concentration maxima in summer was twice the average (2650±50 cm-3). A trajectory-based approach was applied for source identification. Potential Source Contribution Function (PSCF) analysis was performed to estimate the possible contribution of long-range and local PNC transport to PNC concentrations recorded at the marine background site. The PSCF results showed that the marine boundary layer was not seriously affected by long-range transport, but that local transport of air pollution was recognized as an important factor. North Atlantic and Sea-Marine type clusters respectively represented 32.1% and 17.9% of the total PNC spectra and were characterized by the lowest PNCs (1080±1340 and 1210±1040 cm-3 respectively) among all clusters. Wavelet transformation analysis of 1-h aerosol PNC indicated that while the 16-h scale was a constant feature of aerosol PNC evolution in spring, the longer (∼60-h) scales appeared mainly over the whole year (except June). Principal component analysis (PCA) revealed a strong correlation between PNC and NaCl, highlighting the influence of sea-salt aerosols. In addition, PCA also showed that PNC depended on optical and meteorological parameters such as UVR and temperature.

Observations of new particle formation events in the south-eastern Baltic Sea

Plauškaite K., Ulevicius V., Špirkauskaite N., Byčenkiene S., Zieliński T., Petelski T., Ponczkowska A.

Oceanologia

2010

No. 52 (1)

53-75

New particle formation and growth were observed at a coastal site (Preila station, Lithuania) during 1997 and 2000-2002. The total amount of data analysed covers 291 one-day periods, 45 (15%) of which were long-term, new particle formation days. Short-term nucleation events (from a few minutes to one hour) and long-term events (from one to eight hours) were identified. The mean particle growth rate, condensation sink and condensable vapour source rate during nucleation events were 3.9 nm h*-1, 1.45 × 10*-3 cm*-3 s-1 and 7.5 x 104 cm-3 s-1 respectively. The average formation rate J_10 was 0.4 cm-3 s-1. The nucleation events were accompanied mainly by air masses transported from the north (43%) and north-west (19%). Meteorological parameters and trace gas (O3, SO2, NO2) concentrations were also analysed. It was found that nucleation events are related to high levels of solar radiation.