The CCI concept schemes are used to define concepts within an element of a Directory Reference Scheme. There are currently eight concept schemes defined: data type, ecv, frequency, institutes, platforms, processing levels, products, and sensors. The use of a concept scheme allows easy navigation up and down the tree.
As well as being concepts the the concepts are also named individuals of the CCI Ontology classes.
IRI: http://vocab.ceda.ac.uk/scheme/cci/dataType