  We outline our techniques to characterise photospheric granulation as an
astrophysical noise source. A four component parameterisation of granulation is
developed that can be used to reconstruct stellar line asymmetries and radial
velocity shifts due to photospheric convective motions. The four components are
made up of absorption line profiles calculated for granules, magnetic
intergranular lanes, non-magnetic intergranular lanes, and magnetic bright
points at disc centre. These components are constructed by averaging Fe I $6302
\mathrm{\AA}$ magnetically sensitive absorption line profiles output from
detailed radiative transport calculations of the solar photosphere. Each of the
four categories adopted are based on magnetic field and continuum intensity
limits determined from examining three-dimensional magnetohydrodynamic
simulations with an average magnetic flux of $200 \mathrm{G}$. Using these four
component line profiles we accurately reconstruct granulation profiles,
produced from modelling 12 x 12 Mm$^2$ areas on the solar surface, to within
$\sim \pm$ 20 cm s$^{-1}$ on a $\sim$ 100 m s$^{-1}$ granulation signal. We
have also successfully reconstructed granulation profiles from a $50
\mathrm{G}$ simulation using the parameterised line profiles from the $200
\mathrm{G}$ average magnetic field simulation. This test demonstrates
applicability of the characterisation to a range of magnetic stellar activity
levels.
