Unidata’s Network Common Data Form (netCDF) is a set of software libraries and a machine-independent data format that support the creation, access, and sharing of array-oriented scientific data. This record describes the data format and not the software libraries. The netCDF Data Model is also a community standard for sharing scientific data. The data model of dimensions, variables, and attributes, which define the The Classic Model, was extended starting with netCDF-4.0. The new The Enhanced Data Model supports the classic model in a completely backward-compatible way, while allowing access to new features such as groups, multiple unlimited dimensions, and new types, including user-defined types. For maximum interoparability with existing code, new data should be created with the The Classic Model. The Classic Model was introduced with the very first netCDF release, and is still the core of all netCDF files.