Correcting observatory data prior to scientific analyses

Macmillan, Susan; Dawson, Ewan; Humphries, Thomas; Reay, Sarah; Exton, Jane; Olsen, Nils. 2013 Correcting observatory data prior to scientific analyses. [Poster] In: International Association of Geomagnetism and Aeronomy XIIth Scientific Assembly, Merida, Mexico, 26-31 August 2013. British Geological Survey. (Unpublished)

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Using geomagnetic data submitted to the World Data Centre (WDC) for Geomagnetism in Edinburgh (part of the ICSU World Data System) we have undertaken two campaigns to identify potential measurement problems which may have an impact on the outcome of subsequent scientific analyses. The first campaign concerned the detailed checking of observatory hourly means, initially focussing on the satellite era (late 1990s onwards), but latterly going back in time to the earliest values in the 1880s. Particular attention is paid to identifying steps, spikes and drifts and the emphasis is on deriving multi-year series of geomagnetic field measurements uncontaminated by these measurement artefacts. For the satellite era residuals to hourly models fitted to the observatory data were examined in detail. The second campaign concerned the preliminary checking of observatory minute means, in particular detecting large spikes in the data by annual global coherence tests. These may have a strong effect on analyses involving any extreme value statistics widely used in deriving worst-case space weather scenarios. These data extend back to the late 1960s. In both cases corrections have been made to the WDC holdings, with appropriate updates to relevant metadata and retention of earlier versions of the files offline. Data can be downloaded from

Item Type: Publication - Conference Item (Poster)
Additional Keywords: ICSU World Data System
NORA Subject Terms: Data and Information
Date made live: 20 Aug 2013 16:04 +0 (UTC)

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