ICOS Cities sensor network interim data specification – Version 1.2

ICOS Cities is a pilot project involving three European cities of different sizes in three countries – Zürich (Switzerland), Munich (Germany), and Paris (France).[1] A component of the ICOS Cities is the deployment and operation of outdoor carbon dioxide (CO2) sensor networks in the three cities. The final data transmission and storage infrastructure for ICOS Cities has yet to be formalised and implemented, however, there is an interim need to ensure the data generated by the three sensor networks are provided to data users in a near-identical way for convenient and easy use. This document outlines a technical specification of the data units that should be provided by the data managers of the three sensor networks. Metadata such as information about the sensors, the sites where sensors are installed, and the observational time series data are specified. There has been an effort to keep data formats and the data model simple, while also allowing for conforming to the future data infrastructure that will become available in 2024 via ICOS’s Carbon Portal.