Title Deposition velocity of ultrafine particles measured with the eddy-correlation method over the Nansen ice sheet (Antarctica)
Author Contini, D.; Donateo, A.; Belosi, F.; Grasso, F.M.; Santachiara, G.; Prodi, F.
Author Affil Contini, D., Istituto di Scienze dell'Atmosfera e del Clima, Consiglio Nazionale delle Ricerche, Lecce, Italy. Other: , Italy
Source Journal of Geophysical Research, 115(D16), Citation D16202. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0148- 0227
Publication Date 2010
Notes In English. 51 refs. Ant. Acc. No: 91597. GeoRef Acc. No: 310419
Index Terms aerosols; clouds (meteorology); condensation; grain size; ice; particles; pollution; remote sensing; snow; turbulence; Antarctica; air pollution; clouds; concentration; deposition; digital data; Nansen ice sheet; transport; wind transport; winds
Abstract This work reports an analysis of the concentration, size distribution, and deposition velocity of atmospheric particles over snow and iced surfaces on the Nansen Ice Sheet (Antarctica). Measurements were performed using the eddy-correlation method at a remote site during the XXII Italian expedition of the National Research Program in Antarctica (PNRA) in 2006. The measurement system was based on a condensation particle counter (CPC) able to measure particles down to 9 nm in diameter with a 50% efficiency and a Differential Mobility Particle Sizer for evaluating particle size distributions from 11 to 521 nm diameter in 39 channels. A method based on postprocessing with digital filters was developed to take into account the effect of the slow time response of the CPC. The average number concentration was 1338 cm-3 (median, 978 cm-3; interquartile range, 435-1854 cm-3). Higher concentrations were observed at low wind velocities. Results gave an average deposition velocity of 0.47 mm/s (median, 0.19 mm/s; interquartile range, -0.21 -0.88 mm/s). Deposition increased with the friction velocity and was on average 0.86 mm/s during katabatic wind characterized by velocities higher than 4 m/s. Observed size distributions generally presented two distinct modes, the first at approximately 15- 20 nm and the second (representing on average 70% of the total particles) at 60-70 nm. Under strong-wind conditions, the second mode dominated the average size distribution.
URL http://hdl.handle.net/10.1029/2009JD013600
Publication Type journal article
Record ID 65007178