The Terrestrial Refraction has an influence on the observations. But distorted images reveal strong refraction. The signs of low standard refraction are clear and stable images. Under these conditions the observations agree very well with the Globe Model.
To get the same observations on a Flat Earth, the Refraction in the whole atmosphere would have to be physically impossible strongly negative. See Refraktion in the Flat Earth Model.
All data and observations agree with the predictions of the Globe Model, which includes Terrestrial Refraction. The predictions for the Flat Earth Model, however, contradict the observations.
The Rainy Lake Experiment shows even better than the Bedford Level Experiment that the earth is a globe, since we also have GPS measurements that are not influenced by Refraction or Perspective, but are of a pure geometric nature. GPS measurements directly provide the radius of the earth.
Only one conclusion remains:
The earth cannot be flat, but is a globe with a mean radius of 6371 km!