Metadata in geomagnetism : experiences of the World Data Centre for Geomagnetism, Edinburgh

Abstract

Geomagnetic observatory data dates back more than 150 years. However, since the advent of digital recordings in the 1960s these data have become increasingly separated from their associated metadata. Traditionally, information about an observatory’s instrumentation, data processing history, quality control methods, environment, housing, staffing etc. where noted annually in observatory yearbooks. Whilst many observatories still produce these documents many no longer record metadata in this way. In addition, subsequent changes made to datasets and then submitted to World Data Centres (WDC), have not been well documented leading to discrepancies between different data centres. Furthermore, known issues with particular datasets cannot be highlighted for current or future researchers as there are limited metadata held with or within digital data files. This paper describes the current efforts by the WDC for Geomagnetism, Edinburgh, to improve its holdings with these vital metadata. We describe how we are now collecting and distributing various metadata via our WDC web pages. We also discuss some of the difficulties in capturing, storing and distributing geomagnetic metadata. The time-varying aspect to these data is a great challenge in this regard and is not something well captured in current metadata standards used for geospatial data. We wish to encourage observatory operators to record these vital metadata in some form or another (yearbooks, free-form text etc) and the geomagnetism community to help establish some standard for the level of metadata recorded