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