Characterization of aerosols at a coastal site near Vindeby (Denmark)

Aerosol particle size distributions and aerosol chemical composition were measured with optical particle counters and filter packs, respectively, on an offshore mast in the Danish coastal waters near Vindeby on the island of Lolland. The filter pack samples were analyzed for ions representative of marine and continental aerosol: Na+, Cl-, SC4-, NO3-, and NH4+. The physical and chemical measurements are complementary, and the information on chemical composition, together with the local meteorological parameters, the synoptic situation, and air mass trajectories, is crucial for interpreting the observed variations in the particle concentrations. Considering these sets of data, four periods can be discerned during the experiment. Further, the aerosol concentrations vary with wind speed, as is expected for marine aerosols, depending strongly on the fetch. In the case of short fetch, the coarse aerosol fraction (diameter >1 μm) and the fine aerosol fraction (0.2-1 μm) decrease with wind speed. Processes like advection, diffusion, and dry deposition cannot explain the strong dependence of the concentrations on wind speed. Apparently, uncertainties in the source strength and origin of aerosol advected across the shore line, as well as processes affecting the aerosol concentrations over land, such as variability in the sources, washout by rain, and other removal and transport mechanisms, have much more influence than the transport and removal over water. Copyright 1999 by the American Geophysical Union.

[1]  E. Houde,et al.  Modeling particles and pelagic organisms in Chesapeake Bay: Convergent features control plankton distributions , 1999 .

[2]  G. Leeuw,et al.  Coastal aerosols, air mass history and meteorological conditions , 1997 .

[3]  A. Flossmann,et al.  Venting of gases by convective clouds , 1996 .

[4]  R. Hillamo,et al.  Distribution of nitrate over sea-salt and soil derived particles — Implications from a field study , 1996 .

[5]  Edgar L. Andreas,et al.  The spray contribution to net evaporation from the sea: A review of recent progress , 1995 .

[6]  J. Christensen,et al.  Modelling of the end products of the chemical decomposition of DMS in the marine boundary layer , 1994 .

[7]  S. Larsen,et al.  Horizontal transport modelling and exchange of atmospheric nitrogen gases with the coastal ocean , 1994 .

[8]  Gerrit de Leeuw.  Aerosol effects on electro-optical propagation over sea (Invited Paper) , 1993 .

[9]  M. H. Smith,et al.  Marine aerosol concentrations and estimated fluxes over the sea , 1993 .

[10]  Gerrit de Leeuw,et al.  Modeling aerosol particle size distributions over the North Sea , 1992 .

[11]  M. H. Smith,et al.  North atlantic aerosol remote concentrations measured at a hebridean coastal site , 1991 .

[12]  S. Jennings,et al.  Physical characteristics of the ambient aerosol at Mace Head , 1991 .

[13]  T. Iversen.  Calculations of long-range transported sulphur and nitrogen over Europe. , 1990 .

[14]  J. W. Fitzgerald,et al.  Aerosol size distributions and optical properties found in the marine boundary layer over the Atlantic Ocean , 1990 .

[15]  R. Harrison,et al.  Field intercomparison of filter pack and denuder sampling methods for reactive gaseous and particulate pollutants , 1990 .

[16]  W. John,et al.  Measurement of aerosol size distributions for nitrate and major ionic species , 1988 .

[17]  J. Seinfeld.  Atmospheric Chemistry and Physics of Air Pollution , 1986 .

[18]  K. Davidson,et al.  Observational Results On The Influence Of Surface Layer Stability And Inversion Entrainment On Surface Layer Marine Aerosol Number Density (1 Micrometer) , 1983 .

[19]  J. Prospero,et al.  Particle size distribution of nitrate and sulfate in the marine atmosphere , 1982 .

[20]  W. Slinn,et al.  Predictions for particle deposition on natural waters , 1980 .

[21]  J. W. Fitzgerald.  Approximation Formulas for the Equilibrium Size of an Aerosol Particle as a Function of Its Dry Size and Composition and the Ambient Relative Humidity , 1975 .