An attribute has a name, type, and values. Attributes are used to specify such properties as units, standard names (that identify types of quantity), special values, maximum and minimum valid values, scaling factors, offsets, and measurement parameters.

• Like variables, the type of an attribute may be one of char, byte, short, int, float, or double for the classic model, or additionally unsigned byte, unsigned short, unsigned int, int64, unsigned int64, string, or user-defined type for the enhanced model.
• An attribute may have multiple values, but attributes cannot be multidimensional.
• Global attributes apply to a whole file. Variable attributes apply to a specific variable.
• NetCDF conventions are defined primarily in terms of attributes. Thus the names of attributes are standardized rather than the names of variables.
• Attributes cannot have attributes.
• Attributes are scalars or 1-D arrays.

2010 Unidata NetCDF Workshop > The Two NetCDF Data Models