The marine network consist of a variety of ships and fixed station installations covering the open ocean and coastal areas, and for this purpose the network is divided into 2 categories; Ships of Opportunity (SOOP; previously known as VOS) and Fixed Ocean Stations (FOS). For each category the required parameters (called core parameters) and the frequency of measurements are defined in the tables in the ICOS Marine Labeling Stage 2 document. The tables also defines the criteria to become a Class 1 and Class 2 station. This classification is a part of the ICOS station labelling process.
