Preface

<p>Repeat station measurements are designed specifically to represent and model the geomagnetic field and its secular variations on a regional scale with a level of detail that would not be achievable using only data from permanent geomagnetic observatories. Although geomagnetic repeat station surveys have a long tradition in many European countries, they were carried out independently in the individual countries. For this reason, it has been difficult for a long time to use the data efficiently for studies of geomagnetic secular variations of the whole European continent. […]