  Atmospheric scintillation caused by optical turbulence in the Earth's
atmosphere can be the dominant source of noise in ground-based photometric
observations of bright targets, which is a particular concern for ground-based
exoplanet transit photometry. We demonstrate the implications of atmospheric
scintillation for exoplanet transit photometry through contemporaneous
turbulence profiling and transit observations. We find a strong correlation
between measured intensity variations and scintillation determined through
optical turbulence profiling. This correlation indicates that turbulence
profiling can be used to accurately model the amount of scintillation noise
present in photometric observations on another telescope at the same site. We
examine the conditions under which scintillation correction would be beneficial
for transit photometry through turbulence profiling, and find that for the
atmosphere of La Palma, scintillation dominates for bright targets of magnitude
above $V\sim10.1$ mag for a 0.5~m telescope, and at $V\sim11.7$ mag for a 4.2 m
telescope under median atmospheric conditions. Through Markov-chain Monte Carlo
methods we examine the effect of scintillation noise on the uncertainty of the
measured exoplanet parameters, and determine the regimes where scintillation
correction is especially beneficial. The ability to model the amount of noise
in observations due to scintillation, given an understanding of the atmosphere,
is a crucial test for our understanding of scintillation and the overall noise
budget of our observations.
