  Visible-light-absorbing carbonaceous aerosols within the boundary layer
affect the radiance and polarization states of the radiation at the top of the
atmosphere. Remote sensing from suborbital and satellite-based platforms
utilizes these radiance and polarization signals to retrieve the key properties
of these aerosols. Recent retrieval algorithms have shown a progressive trend
toward including multi-angular and multi-spectral polarimetric measurements to
produce better retrieval accuracy in comparison to those using measurements
based on a single viewing angle. Here, we perform a theoretical investigation
of the top of atmosphere (TOA) radiance-related reflectance factor
(bidirectional reflectance factor (BRF)) and the two types of
polarimetry-related factors (polarized bidirectional reflectance factor (pBRF)
and the degree of linear polarization (DoLP)) for different types of
atmospheric light-absorbing carbonaceous aerosols as a function of particle
size distribution. We selected three polarimetric bands corresponding to those
utilized by NASA Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) --
near-UV (470 nm), visible (660 nm), and near-infrared (865 nm) -- for our
simulations which were performed over ocean surface using the successive order
of scattering (SOS) algorithm coupled to a Lorenz-Mie aerosol optics model. The
analysis of particle phase matrix elements indicates a close relationship
between the angular dependencies of DoLP and associated phase matrix components
at the shortest polarimetric band (470 nm). Using Jacobian analysis, we find
that the radiance- and polarimetry-related reflectance factors of weakly
light-absorbing aerosols, such as brown carbon, are more sensitive to changes
in particle size and imaginary refractive index in comparison with those of
black carbon, which is strongly light-absorbing.
