  Ultra-hot Jupiters have recently attracted interest from observers and
theoreticians alike, as they provide observationally accessible test cases. We
apply a hierarchical modelling approach as a virtual laboratory to study cloud
formation and gas-phase chemistry. We utilise 97 vertical 1D profiles of a 3D
GCM for HAT-P-7b to evaluate our kinetic cloud formation model consistently
with the local equilibrium gas-phase composition. The day/night temperature
difference on HAT-P-7b (~ 2500K) causes clouds to form on the nightside
(dominated by H2/He) while the dayside (dominated by H/He) retains cloud-free
equatorial regions. The cloud particles vary in composition and size throughout
the vertical extension of the cloud, but also globally.
TiO2[s]/Al2O3[s]/CaTiO3[s]-particles of cm-sized radii occur in the higher
dayside-latitudes, resulting in a dayside dominated by gas-phase opacity. The
opacity on the nightside, however, is dominated by 0.01 ... 0.1 mum particles
made of a material mix dominated by silicates. The gas pressure at which the
atmosphere becomes optically thick is ~1d-4 bar in cloudy regions, and ~0.1 bar
in cloud-free regions. HAT-P-7b features strong morning/evening terminator
asymmetries, providing an example of patchy clouds and
azimuthally-inhomogeneous chemistry. The large temperature differences result
in an increasing geometrical extension from the night- to the dayside. The
chemcial equilibrium H2O abundance at the terminator changes by < 1 dex with
altitude and < 0.3 dex (a factor of 2) across the terminator for a given
pressure, indicating that H2O abundances derived from transmission spectra can
be representative of the well-mixed metallicity at P > 10 bar. We suggest the
atmospheric C/O as an important tool to trace the presence and location of
clouds in exoplanet atmospheres. Phase curve variability of HAT-P-7b is
unlikely to be caused by dayside clouds.
