dim1: [dim2: [dim3: ...] ] method [(comment)]where brackets indicate optional words. The valid values for dim1 [dim2 [dim3 ...] ] are dimension names of the associated variable or valid standard names. The valid values of method are contained in Appendix D. When the method refers to a climatological time axis, the values in Appendix D may have the suffixes "within days", "over days", "within years", or "over years" or appended.
([interval: value unit [interval: ...] comment:] remainder)The remainder text is not standardized. If no interval clauses are present, the entire comment is therefore not standardized. There may be zero interval clauses, one interval clause, or exactly as many interval clauses as there are dims to which the method applies. The value must be a valid number and the unit a string that is recognizable by the udunits package.