SEACOOS CDL v2.0 December 9, 2004 20 11. Standard Names The main purpose of CF is for the climate and forecast data. Many ocean observing and instrument-specific standard names are missing from the CF standard name set.  SEACOOS CDL digresses from CF on this point.  SEACOOS CDL gets standard name entries from the SEACOOS Data Dictionary. This data dictionary contains names and definitions that the variable attribute :standard_name can be given the appropriate unique identifier of the variable’s content.     The SEACOOS Data Dictionary also provides other useful metadata about each va riable that give suggested entries to include in variable attribute fields of a netCDF file. These are physical measurement units (:units), geophysical data ranges (:valid_range), reference datum (:reference), variable long name or description (:long_name) and variable abbreviation (:short_name).   In addition, the SEACOOS Data Dictionary functions to associate the given standard name with what other conventions and standards define as the same or similar variable.  The ability to associate or correlate dictionaries is one of the unique aspects of the SEACOOS Data Dictionary. The online SEACOOS Data Dictionary can be accessed at http://seacoos.org/documents/seacoos-data-dictionary-v2dot0/ 12. Units The Unidata units library, udunits, supports conversion of unit specifications between formatted and binary forms, arithmetic manipulation of unit specifications, and conversion of values between compatible scales of measurement.  Each variable in the netCDF file is required to have a units attribute.  The units attribute is a string that is recognized by  the udunits package as specified by the CF Conventions. The udunits package includes a file udunits.dat which lists its supported unit names.  The library  is available from http://www.unidata.ucar.edu/packages/udunits/. 13. Future Directions The SEACOOS CDL was originally drafted to coordinate many SEACOOS data sources.  Some aspects were overlooked while other aspects were purposefully simplified in the first and second round drafts so other processes could be developed.  Future directions and topics to include in the SEACOOS CDL, but not limited to, are: ·    Guidelines for QA/QC variables ·    Relax time constraint to other time frames ·    Expand format categories to include model  output.