Aerosol size distribution. Two columns are expected: The radius
and the particle number. Together with aerosol_refrac_index oraerosol_refrac_file this forms the input to Mie calculations of the
aerosol optical properties. Please note that
only the single-scattering albedo, the scattering phase function, and the
wavelength-dependence of the extinction coefficient are affected by the Mie calculation
while the absolute value of the extinction coefficient is taken from other sources;
generally, the extinction coefficient at the first internal wavelength is
taken from whatever is available (either default Shettle (1989) or user-defined);
the extinction at all other wavelengths is scaled according to the Mie calculation.
For this reason, the absolute numbers are not relevant - only the shape of the
size distribution matters. For details see also the description of aerosol_refrac_file.
It is recommended to avoid this option and rather to calculate the aerosol optical
properties externally e.g. with mie and to pass them to uvspec with aerosol_files.
Arve Kylling
2010-03-10