  The atmospheric pressure fluctuations on Mars induce an elastic response in
the ground that creates a ground tilt, detectable as a seismic signal on the
InSight seismometer SEIS. The seismic pressure noise is modeled using Large
Eddy Simulations of the wind and surface pressure at the InSight landing site
and a Green's function ground deformation approach that is subsequently
validated via a detailed comparison with two other methods based on Sorrells'
theory (Sorrels 1971; Sorrels et al. 1971). The horizontal acceleration as a
result of the ground tilt due to the LES turbulence-induced pressure
fluctuations are found to be typically ~2 - 40 nm/s^2 in amplitude, whereas the
direct horizontal acceleration is two orders of magnitude smaller and is thus
negligible in comparison. The vertical accelerations are found to be ~0.1 - 6
nm/s^2 in amplitude.
  We show that under calm conditions, a single-pressure measurement is
representative of the large-scale pressure field (to a distance of several
kilometers), particularly in the prevailing wind direction. However, during
windy conditions, small-scale turbulence results in a reduced correlation
between the pressure signals, and the single-pressure measurement becomes less
representative of the pressure field. Nonetheless, the correlation between the
seismic signal and the pressure signal is found to be higher for the windiest
period because the seismic pressure noise reflects the atmospheric structure
close to the seismometer. In the same way that we reduce the atmospheric
seismic signal by making use of a pressure sensor that is part of the InSight
APSS (Auxiliary Payload Sensor Suite), we also the use the synthetic noise data
obtained from the LES pressure field to demonstrate a decorrelation strategy.
