Apparatus for dry deposition of aerosols on snow
Abstract. Deposition of light-absorbing aerosol on snow can drastically
change the albedo of the snow surface and the energy balance of the snowpack.
To study these important effects experimentally and to compare them with theory,
it is desirable to have an apparatus for such deposition experiments. Here,
we describe a simple apparatus to generate and evenly deposit light-absorbing
aerosols onto a flat snow surface. Aerosols are produced (combustion
aerosols) or entrained (mineral dust aerosols) and continuously transported
into a deposition chamber placed on the snow surface where they deposit onto
and into the snowpack, thereby modifying its surface reflectance and albedo.
We demonstrate field operation of this apparatus by generating black and
brown carbon combustion aerosols and entraining hematite mineral dust aerosol
and depositing them on the snowpack. Changes in spectral snow reflectance are
demonstrated qualitatively through pictures of snow surfaces after aerosol
deposition and quantitatively by measuring hemispherical-conical reflectance
spectra for the deposited areas and for adjacent snowpack in its natural
state. Additional potential applications for this apparatus are mentioned and
briefly discussed.