SEACOOS CDL v2.0 December 9, 2004 18 :data_type Text. This attribute was initially intended to help describe type the type of instrument or package of instruments used to collect the data in the dataset but can ultimately be deprecated by use of “:platform_code” and “ :package_code” attributes.  Example: “met” 10. Variable Attributes In this section the required and recommended variable attributes are described. An example entry is provided for each description. They provide specific information about a variable. Whenever an attribute is present as both a global and variable attribute, the variable attribute takes precedence. The CDL notation for defining a variable attribute is variable_name:attribute_name = list_of_values; 10.1 Required Variable Attributes The following required variable attributes should be present with each netCDF variable so that either one can obtain mo re information about the dataset or automated software can process the attributes.  If an attribute does not have a value, an option for each variable attribute will be the “not applicable” statement  . :standard_name Text. A unique  string that unambiguously identifies the physical nature of the variable stored in the dataset.  Only one valid standard name chosen from the SEACOOS Data Dictionary can be used.  The SEACOOS Data Dictionary is discussed in Section 11. In case that no standard name is provided in the Data Dictionary, place “none” in the text field. No spaces or tabs are allowed in the value string. Example: “water_temperature” or “northward_current” or “none” :units Text. The physical units of the variable stored in the dataset.  In the case of dimensionless units, place “none”   in the text field. The text string should conform to Unidata’s  udunits package to maintain portability of the data units described. More information about Unidata’s  udunits package is provided in Section 12.   Example: “m s-1” “meter second-1” or “none” 10.2 Other Variable Attributes Some of the following variable attributes may be recommended while others may be required for a specific dataset variable, for example water- level or format category, for example fixed-point observation. :long_name Text. Descriptive name that indicates the variable’ s content which, for example, may be used for labeling plots. Example: “Sea Surface Temperature”;