The RSP instrument counts were corrected for dark
current and reduced to calibrated reflectances. These
reflectance measurements contain contributions from
both the surface and the atmosphere. The atmospheric
contribution is well characterized by the MFRSR
measurements, which provide accurate estimates of
aerosol optical depth and allow a plausible aerosol
microphysical model to be inferred. The atmospheric
reflectance was then calculated using a vector
adding/doubling code [Cairns et. al. 1997]. The model
atmosphere that is used consists of a two layer
atmosphere with a pure molecular layer above the
aircraft and an aerosol layer mixed with the remaining
molecular contribution below the aircraft. The vertical
distribution of scattering properties is reasonable for the
suppressed boundary layer that was observed and the
aerosol properties were defined by the MFRSR
measurements. The calculated atmospheric reflectance
was then used to correct the RSP measured
reflectances so that they provide a reasonable estimate
of the surface reflectance [Hu et. al. 1999], particularly
for the low aerosol load (optical depth of 0.14 at 550nm)
on 10/14/1999.
a