17 Degree Isotherm Depth:

The depth of the 17 degree (C) isotherm is calculated from 
temperature profiles using linear interpolation of 
depth vs temperature. The maximum distance between 
temperatures is 50m, and is typically 20 or 25 meters.

In ascii format files, to the right of the data, you will 
find data quality codes which use the definitions below. 
Using these codes you can tune your analysis to trade-off 
between quality and temporal/spatial coverage. 

Quality Code Definitions:

0 = datum missing

1 = highest quality; Pre/post-deployment calibrations agree to within
sensor specifications.  In most cases only pre-deployment calibrations have
been applied

2 = default quality; Pre-deployment calibrations applied.  Default
value for sensors presently deployed and for sensors which were either not
recovered or not calibratable when recovered.

3 = adjusted data; Pre/post calibrations differ, or original data do
not agree with other data sources (e.g., other in situ data or climatology),
or original data are noisy. Data have been adjusted in an attempt to
reduce the error.

4 = lower quality; Pre/post calibrations differ, or data do not agree
with other data sources (e.g., other in situ data or climatology), or data
are noisy.  Data could not be confidently adjusted to correct for error.

5 = sensor or tube failed