The original data in the F291 format have been converted to NetCDF by using the
F291NC program version 0.4.1.  F291NC was developed by NCEI, utilizing
information from the original F291 format specification available at
https://www.nodc.noaa.gov/General/NODC-Archive/f291.html to map fields to the
NCEI TimeSeries Orthogonal v2.0 NetCDF Template.  The software extracted data
from the fields in each original F291 file and copied those data to fields into
their corresponding NetCDF file.  The best effort was made to take into account
the requirements and limitations of the F291 format, such that the resulting
NetCDF file would represent the original data as closely as possible, except for
the ten minute averages of wind direction and wind speed appearing in Record
Type J.  The ten minute averages are prefixed with FIRST, SECOND, ..., and
SIXTH.  After ten minutes, the FIRST AVERAGE of the prior F291 record appears as
the SECOND AVERAGE of the current F291 record, SECOND AVERAGE as THIRD AVERAGE,
..., and FIFTH AVERAGE as SIXTH AVERAGE.  This shift of ten minute averages
introduces redundant data points.  Following how the National Data Buoy Center
stores the ten minute averages in their NetCDF files in January 2011 and
afterwards, we filtered out redundant data and placed the ten minute averages of
wind speed and wind direction to the continuous_wind_speed and
continute_wind_direction NetCDF arrays, respectively.  This improvement not only
reduces the size of resulting NetCDF files but also provides a convenient way to
access the averages.  Processing messages, warnings and errors were captured to
log files, one per original F291 data file.