Adjust the surface according to given radiative fluxes.
sw_down (float) – Shortwave downward flux [W / m**2].
sw_up (float) – Shortwave upward flux [W / m**2].
lw_down (float) – Longwave downward flux [W / m**2].
lw_up (float) – Longwave upward flux [W / m**2].
timestep (float) – Timestep in days.