• Not variable names, but values for the standard_name attribute of variables
• standard_name attribute identifies the physical quantity of a variable, for example "air_temperature", "divergence_of_wind", "plant_respiration_carbon_flux", or "tendency_of_atmosphere_mass_content_of_particulate_organic_matter_dry_aerosol_due_to_net_production_and_emission".
• CF standard name table includes a precise definition of each quantity named, e.g. for the standard_name above:

  "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). Aerosol takes up ambient water (a process known as hygroscopic growth) depending on the relative humidity and the composition of the aerosol. "Dry aerosol" means aerosol without water. "Net production" means the net result of all chemical reactions within the atmosphere that produce or destroy a particular species. "Emission" means emission from a primary source located anywhere within the atmosphere, including at the lower boundary (i.e. earth's surface). "Emission" is a process entirely distinct from "re-emission" which is used in some standard names. "particulate_organic_matter_dry_aerosol" means all particulate organic matter dry aerosol except black carbon. It is the sum of primary_particulate_organic_matter_dry_aerosol (which is emitted into the atmosphere) and secondary_particulate_organic_matter_dry_aerosol (which is produced within the atmosphere).

• The standard name is independent of units of measure, which are specified in the units attribute, e.g. "kg m-2 s-1"
• The standard name is also independent of coordinate variables used to describe its variation.
• There are Guidelines for constructing CF standard names, and anyone can propose and justify the need for new names.
• As a standard for naming physical quantities, the table of names and definitions is independent of netCDF.

2009 Unidata NetCDF Workshop for Developers and Data Providers > CF Conventions