  In this paper, we study the properties of solar granulation in a facular
region from the photosphere up to the lower chromosphere. Our aim is to
investigate the dependence of granular structure on magnetic field strength. We
use observations obtained at the German Vacuum Tower Telescope (Observatorio
del Teide, Tenerife) using two different instruments: Triple Etalon SOlar
Spectrometer (TESOS), in the BaII 4554 A line to measure velocity and intensity
variations along the photosphere; and, simultaneously, Tenerife Infrared
Polarimeter (TIP-II), in the FeI 1.56 $\mu$m lines to the measure Stokes
parameters and the magnetic field strength at the lower photosphere. We obtain
that the convective velocities of granules in the facular area decrease with
magnetic field while the convective velocities of intergranular lanes increase
with the field strength. Similar to the quiet areas, there is a contrast and
velocity sign reversal taking place in the middle photosphere. The reversal
heights depend on the magnetic field strength and are, on average, about 100 km
higher than in the quiet regions. The correlation between convective velocity
and intensity decreases with magnetic field at the bottom photosphere, but
increases in the upper photosphere. The contrast of intergranular lanes
observed close to the disc center is almost independent of the magnetic field
strength. The strong magnetic field of facular area seems to stabilize the
convection and to promote more effective energy transfer in the upper layers of
the solar atmosphere, since the convective elements reach larger heights.
