Circumpolar transport and air-surface exchange of atmospheric mercury at Ny-Ålesund (79° N), Svalbard, spring 2002 J. Sommar1, I. Wängberg2, T. Berg3, K. Gårdfeldt1, J. Munthe2, A. Richter4, A. Urba5, F. Wittrock4, and W. H. Schroeder6 1Department of Chemistry, Göteborg University, Kemivägen 4, 41296 Göteborg, Sweden 2IVL Swedish Environmental Research Institute, P.O. Box 47086, 40258 Göteborg, Sweden 3Norwegian Institute for Air Research (NILU), P.O. Box 100, 2027 Kjeller, Norway 4Institute of Environmental Physics, University of Bremen, NW1, Otto-Hahn-Allee 1, 28359 Bremen, Germany 5Ecological Spectroscopy Laboratory, Institute of Physics, Gostauto 12, 2600 Vilnius, Lithuania 6Environmental Canada: Meteorological Service of Canada, 4905 Dufferin Street, Toronto, Canada
Abstract. Mercury in different environmental compartments has been measured at
Ny-Ålesund (78°54' N, 11°53' E) during an intensive campaign,
17 April to 14 May 2002. Time-resolved speciated determination of mercury
in the atmosphere and snow was conducted at the Norwegian research station
at the Zeppelin mountain, 474 m above the sea level, and at the Italian
research facility Dirigibile Italia, 12 m above the sea level. Total Gaseous
Mercury (TGM) was present in the range <0.1 to 2.2 ng m−3 during the
campaign. Three mercury depletion events, identified as periods with
decreased TGM concentrations, were observed. At the lower altitude, TGM
concentrations following such events were found to exhibit both higher
magnitude and larger variability in comparison to results from the Zeppelin
station. Oxidised mercury species in air and fall-out with snow as well as
mercury attached to particles were also measured and their concentrations
were found to be anti-correlated with TGM in air. concentrations of total Hg in snow (Hg-tot)
showed a large (~15×) increase in response to Gaseous Elemental Mercury Depletion
Events (GEMDEs, range 1.5–76.5 ng L−1).
Solid evidence for photo-stimulated emissions of
Hg0(g) from the snow pack in conjunction to depletion events were
obtained from gradient measurements as well as from flux chamber
measurements. Steep diurnal concentration variations of Hg0(aq) in
surface seawater were also found to concur with changing solar radiation.
The concentration of Hg0(aq) in seawater was found to be in the range
12.2–70.4 pg L−1, which corresponds to supersaturation. Hence, the
seawater surface constituted a source emitting elemental mercury.
The concentrations of RGM (reactive gaseous mercury), Hg-p (particulate
mercury), and BrO column densities (detected by DOAS) were very low except
for a few individual samples during the major Hg0 depletion event. BrO vertical column
densities obtained by the remote satellite ESR-2 and trajectory analysis indicate that
the air masses exhibiting low Hg0 concentrations originated from areas with high BrO
Citation: Sommar, J., Wängberg, I., Berg, T., Gårdfeldt, K., Munthe, J., Richter, A., Urba, A., Wittrock, F., and Schroeder, W. H.: Circumpolar transport and air-surface exchange of atmospheric mercury at Ny-Ålesund (79° N), Svalbard, spring 2002, Atmos. Chem. Phys., 7, 151-166, doi:10.5194/acp-7-151-2007, 2007.