A Common Approach to Atmospheric Radar Data from Eiscat and the US Geospace Observatories within the Coopeus Project

The high-latitude atmosphere and ionosphere are important for studies of the relationship between Solar and Terrestrial conditions as well as for understanding the coupling of the different altitude regions in the Earth's atmosphere. A large amount of effort has been dedicated to studies in the polar regions, and more generally the full view of the atmospheric and geospace environment is only possible through international collaborations. Incoherent scatter (IS) radar systems are important research tools in the studies of the upper atmosphere and the ionosphere. The standard high-level data from these systems contain electron density, electron and ion temperatures, and line-of-sight plasma flow as functions of time and altitude. There are about a dozen active ISR systems in the world at the present. Three of these systems are operated in Europe by the EISCAT Scientific Association. These are located in the northernmost region of the Scandinavian peninsula and on Svalbard. EISCAT is also currently preparing for construction of the new multi-static phased array radar EISCAT_3D. MIT Haystack Observatory, Cornell University and SRI International operate the major US incoherent scatter radars, several of which are also located at high latitudes. The European and American IS radar communities are already relatively well integrated and carry out coordinated observations, common workshops and meetings. They all use the Madrigal distributed database system for data archiving and distribution. In order to achieve greater interoperability, shared data structures, practices and standards are developed within the COOPEUS project. Three common levels of IS data exist (raw samples, intermediate correlated data, and analysed data) and the intermediate level has been initially selected for further harmonization. Intermediate level data represent a convenient form for exchange and storage, because the data volume has already been decreased to a more manageable level through temporal and spatial averaging while still retaining sufficient information for further analysis. Goals for future collaborations are to reach further harmonization at higher data levels between different radars, combined with other databases used for space weather research and with databases of other environmental research infrastructures.