Where possible, the units should follow the Unidata udunits standard . This could be used for labelling plots, for example. If present for a variable, this number is to be added to the data after it is read by the application that accesses the data. If present for a variable, the data are to be multiplied by this factor after the data are read by the application that accesses the data. The valid units for time are listed in the Unidata udunits standard .
Plural forms are also acceptable.
There are udunits functions that can interpret and manipulate the time units string. Type is double. If there is no regular time increment, all the elements should be zero-filled. Required only for time-averaged data. The average period represented in the source variable before taking the average.