This directory contains Level 1 QC'd data.

Sounding WND and PTU files have been run through a MATLAB routine to de-bob the data. Output files have PT1 and WN1
suffixes.
PT2 files have had the dew pt temperatures in the file replaced by the RH calculated with respect to ice.
Corresponding plots of these data are in the QC Images directory.

Significant flags in files:

The "T", "U", "d", "f" and "v" would pertain to the reason why a level or data point was determined to be
significant with respect to coding a TEMP or PILOT message. The flag represents a turning point in the
sounding where the parameter deviates from a linearity between points below and points above. The criteria
for determining a deviation from linearity is set by the various weather agencies (NWS,WMO etc..). The various
criteria settings are programmed in the MW15 by default but can be altered if needed. It may be that for some
levels, the tolerance criteria for both humidity and temperature are met so that would result in a "TU" in the
output. If only temperature was varying from a straight line plot, then you would just see a "T" in the output.
The criteria tolerance for temperature by default is 2 degrees and for RH it is 15%.

The wind data is flagged according to whether it was significant due to direction or speed. Wind speed and
direction are computed from the component wind vectors (u and v). You can view the criteria helpline parameters
from Metgraph's dropdown menu:Tools-> Criteria Line. If you have opened the graph for wind speed and direction
you will see the default values of 5 m/s and 10 degrees. If you are viewing the u and v component wind, you will
see the criteria of 2 m/s.

*.cls files are NCAR CLASS formatted files. These were generated using the NCAR Aspen (Atmospheric Sounding
Processing Environment) program. ASPEN is used for analysis and quality control (QC) of sounding data.
http://www.atd.ucar.edu/rtf/facilities/software/aspen/aspen.html

A comparison of these 2 programs shows very similar results.