Climate and Forecast Standard Names
"Mass fraction" is used in the construction "mass_fraction_of_X_in_Y", where X is a material constituent of Y. It is evaluated as the mass of X divided by the mass of Y (including X). It may be expressed as a fraction, a percentage, or any other dimensionless representation of a fraction. Grain-size class distribution is based on the Udden-Wentworth scale.
Mapping to be determined
mass_fraction_of_clay_in_soil