<p>The Solar Forecast Arbiter's preprocessing applies the following
operations to the data:

<ol>
  <li>Apply the <a href="#data-validation">data validation tests</a> and exclude
    the matched data.</li>
  <li>For deterministic forecasts with interval lengths that are longer than
    the observations interval lengths,
    <ol>
      <li>Resample the observations to the forecast using the mean.</li>
      <li>Remove resampled observation data if more than 10% of the
        points in the resampled interval are missing. For example, if 1-minute
        observations are resampled to 60-minute means, then a 60 minute period must
        have no more than 6 minutes of missing data.</li>
    </ol>
  <li>Remove times that do not exist in both the resampled observations,
    the forecasts, and, if selected, the reference forecasts.
  </li>
</ol>
The table below summarizes the data preprocessing results.
</p>
