Product Formatting

The SRAL Level-1 products are supplied in the NetCDF format (version 4).


The NetCDF format is extremely flexible, self-describing and has been adopted as a de-facto standard for many operational oceanography systems. The files will follow the Climate and Forecast NetCDF conventions (CF-1.4) because these conventions provide a practical standard for storing.


A NetCDF file contains named dimensions, variables and attributes. These components can be used together to capture the meaning of data and relationships between data fields in an array-oriented data set.


A dimension may be used to represent a real physical dimension, for example, time, latitude, longitude or height. A dimension might also be used to index other quantities, for example, waveforms index.


Variables are used to store the majority of data in a NetCDF file. A variable represents an array of values of the same type. A scalar value is treated as a zero-dimensional array. A variable has a name, a data type and a shape described by its list of dimensions, specified when the variable is created. A variable may also have associated attributes which may be added, deleted or changed after the variable is created.


NetCDF attributes are used to store information about the data (ancillary data or metadata) and are similar in many ways to the information stored in data dictionaries and schema in conventional database systems. Most attributes provide information about a specific variable. These are identified by the name of that variable, together with the name of the attribute.


Key Resources