Working Group Call Notes: March 14, 2013

IOOS Glider Data Working Group Notes: March 14, 2013

Here are the notes from the March 14 conference call with some additions/suggestions by John Kerfoot and Derrick Snowden. Feel free to edit as you see fit.

1. Agreement on required core variables, named exactly as below:
   a. time (double)
   b. lat (double)
   c. lon (double)
   d. pressure (double)
   e. depth (double)
   f. temperature (double)
   g. conductivity (double)
   h. salinity (double)
   i. trajectory (char)
   

2. Additional variables may be added at data provider discretion, but must be dimensioned properly (ie: time)
a. estimated_depth_averaged_eastward_seawater_velocity: dimensioned along time. Value should be placed midway through the array with _FillValue everywhere else. Allows for TDS aggregation without a new dimension.
b. estimated_depth_averaged_eastward_seawater_velocity: dimensioned along time. Value should be placed midway through the array with _FillValue everywhere else. Allows for TDS aggregation without a new dimension.
c. Use the above referenced variables in version 1.0 of the template and submit the names to CF for consideration. Need to forward a definition of each to Rob Ragsdale (IOOS).

3. Inclusion of variable Quality Control (QC) flags not necessary, but highly recommended. If included, should follow these conventions:
a. Variable name: 'variable_qc', where 'variable' is the name of the data variable. For example, if a QC variable is included for 'temperature', the QC variable name is 'temperature_qc'.
b. Data type: integer
c. Make sure to associate _qc variable with the measured variable via ancillary_variables variable attribute.
d. User-defined flags and meanings via flag_values and flag_meanings variable attributes.

4. Required global attributes:
a. All Highly Recommended, Recommended and Suggested attribues listed at the [ACDD](https://geo-ide.noaa.gov/wiki/index.php?title=NetCDF_Attribute_Convention_for_Dataset_Discovery) website.
b. Additional required global attributes:
i. Conventions: "CF-1.6"
ii. Metadata_Conventions: "Unidata Dataset Discovery v1.0"
iii. Metadata_link: "https://geo-ide.noaa.gov/wiki/index.php?title=NetCDF_Attribute_Convention_for_Dataset_Discovery#Metadata_Link"
iv. featureType: "trajectory" (Allows for recognition of feature type by NetCDF-Java.
v. sea_name (NODC recommended. Current [list](http://www.nodc.noaa.gov/General/NODC-Archive/seanamelist.txt))
vi. file_version: "1.0" (To track changes in file template.)
vii. ioos_regional_association: "SCOOS", etc.

5. Required variable attributes:
a. See associated CDL template
b. coverage_content_type: physicalMeasurement (important for ISO translation to differentiate model results from physical measurements. More info available [here](https://geo-ide.noaa.gov/wiki/index.php?title=NetCDF_Attribute_Convention_for_Dataset_Discovery#Highly_Recommended_Variable_Attributes).

6. Suggestion to include 3 new variables (arrays) dimensioned along a new dimension ('profile') for specifying the profile center latitude, center longitude and center timestamp (ie: TESAC/KKYY messages) to minimize data-user effort for identifying profiles in geographic time/space.

7. File naming convention: Use glider name, serial number, segment/dive time and a flag to indicate real-time vs. delayed data mode. Example:
ru26d-182_yyyymmddTHHMMSS_rt.nc (realtime)
ru26d-182_yyyymmddTHHMMSS_delayed.nc (after recovery)