Level 0: Raw data in proprietary format; suitable for re-processing.

Level 1: Data measured with calibration but no interpretation or assumptions.

Level 2: Data processed with some degree of smoothing, or averaging, or interpretive algorithms.

Level 3: Data packaged for easy access and presentation.

Every data file has an associated metadata file. (NETCDF Structure)

Every data point has a Quality Control index and error estimate.