Format specification for data exchange

This document describes a conceptual framework for specifying exchange data formats, and then gives a detailed description of the standard formats (although there are very important distinctions between measured quantities and those resulting from mathematical model calculations, for simplicity, the two will often be loosely termed "data"). Those considering writing exchange files must review the format options presented in this document and determine the format most suitable for recording their data. If none are deemed suitable, consult with the project archive manager to define a new format option. New file formats will be circulated to project participants as addenda to this document