Results from comparison of geomagnetic hourly mean values

The project

A large number of global hourly mean observatory data is available at the WDC C1 Copenhagen.

Unfortunately, however, these data are not always free of problems, ranging from indiviual outliers perhaps due to errors in data transfer to data not corrected for baseline variations and unreported jumps in the data. In oder to ensure the quality of the available data we performed comparisons between neighbouring observatories. By comparing each observatory data series to those of at least two neighbouring observatories, several problems were detected.

This website is meant as a source of information about identified problems for users of the data. We cannot and will not correct the data.

Our request to geomagnetic observatories

In the interest of global observatory data quality, we strongly encourage all observatories where problems have been identified to:

  • check their original data
  • correct errors, if possible, based on background information on the data
  • provide a corrected data set
  • provide information on the the source of jumps if they cannot be corrected directly

Method and information given on this website

Regional distribution

In order not to lose the overview we divided the world in several zones, comparing observatories within one zone but occasionally including an observatory from a neighbouring zone if the distance was shorter than within the zone.


Zone12 Zone3 Zone4 Zone7 Zone9 Zone13 Zone16 Zone18 Zone17 Zone8 Zone5 Zone1 Zone10 Zone14 Zone15 Zone11 Zone6 Zone2

Time interval

We compared the observatory data year by year, starting with 1995 up to 2003 if the data were available. A rough, graphical overview about the available data reflecting approximately the status of the data we worked on can be found here.


Monika Korte
Group Leader
Dr. Monika Korte
Behlertstraße 3a
Building K 3 , Room 116
14467 Potsdam
+49 331 288-1268