3bc32463-42fe-8d88-e063-3050940ae0be English nonGeographicDataset non geographic dataset British Geological Survey +44 131 667 1000 The Lyell Centre, Research Avenue South EDINBURGH LOTHIAN EH14 4AP enquiries@bgs.ac.uk pointOfContact 2026-05-02 UK GEMINI 2.3 http://data.bgs.ac.uk/id/dataHolding/13608490 Monthly magnetic data from the Greenwich Magnetic Observatory Yearbooks (1841 – 1925) 2025-08-06 creation http://data.bgs.ac.uk/id/dataHolding/13608490 This dataset contains monthly mean magnetic data from the Greenwich Observatory from 1841 to 1925. This dataset is the result of report https://nora.nerc.ac.uk/id/eprint/536965/ and is the published product of a study by the British Geological Survey (BGS). The main aim was to create a digital record of the monthly magnetic data stored in the Greenwich Magnetic Observatory yearbooks for 1841 to 1925, for the magnetic research community to use. The report also details the steps taken to convert the inclination and declination, from various published units to standardised units (arcminutes). We have also attempted to convert the horizontal and vertical force values published from 1868 to 1911 from British, and Gauss units to nanoTeslas, however, due to inconsistencies in the scaling factors, and time constraints, we have had limited success. Post-1912 the horizontal and vertical force data has successfully been converted into nanoTesla. Greenwich Magnetic Observatory (GRW) is located at 51°29'N 0°0'E 0m elevation. Observatory info can be found at: https://geomag.bgs.ac.uk/operations/greenwich.html The observatory yearbooks can be found at: http://www.geomag.bgs.ac.uk/data_service/data/yearbooks/grw.html A report describing this data set and its construction can be found at: https://nora.nerc.ac.uk/id/eprint/536965/ Enquiries British Geological Survey 0115 936 3142 0115 936 3276 The Lyell Centre, Research Avenue South EDINBURGH LOTHIAN EH14 4AP United Kingdom enquiries@bgs.ac.uk distributor Enquiries British Geological Survey 0115 936 3142 0115 936 3276 The Lyell Centre, Research Avenue South EDINBURGH LOTHIAN EH14 4AP United Kingdom enquiries@bgs.ac.uk distributor Enquiries British Geological Survey 0115 936 3142 0115 936 3276 The Lyell Centre, Research Avenue South EDINBURGH LOTHIAN EH14 4AP United Kingdom enquiries@bgs.ac.uk originator Enquiries British Geological Survey 0115 936 3142 0115 936 3276 The Lyell Centre, Research Avenue South EDINBURGH LOTHIAN EH14 4AP United Kingdom enquiries@bgs.ac.uk originator Enquiries British Geological Survey 0115 936 3143 0115 936 3276 Environmental Science Centre, Nicker Hill, Keyworth NOTTINGHAM NOTTINGHAMSHIRE NG12 5GG United Kingdom enquiries@bgs.ac.uk distributor Enquiries British Geological Survey 0115 936 3143 0115 936 3276 Environmental Science Centre, Nicker Hill, Keyworth NOTTINGHAM NOTTINGHAMSHIRE NG12 5GG United Kingdom enquiries@bgs.ac.uk originator Enquiries British Geological Survey United Kingdom not available distributor Enquiries British Geological Survey United Kingdom not available pointOfContact notApplicable https://resources.bgs.ac.uk/images/geonetworkThumbs/3bc32463-42fe-8d88-e063-3050940ae0be.png Geology GEMET - INSPIRE themes, version 1.0 2008-06-01 publication Geomagnetism Geophysics BGS Thesaurus of Geosciences 2022 revision Citable Data NGDC Deposited Data dataCentre NERC_DDC otherRestrictions licenceOGL Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced NERC materials "Contains NERC materials ©NERC [year]" otherRestrictions The copyright of materials derived from the British Geological Survey's work is vested in the Natural Environment Research Council [NERC]. No part of this work may be reproduced or transmitted in any form or by any means, or stored in a retrieval system of any nature, without the prior permission of the copyright holder, via the BGS Intellectual Property Rights Manager. Use by customers of information provided by the BGS, is at the customer's own risk. In view of the disparate sources of information at BGS's disposal, including such material donated to BGS, that BGS accepts in good faith as being accurate, the Natural Environment Research Council (NERC) gives no warranty, expressed or implied, as to the quality or accuracy of the information supplied, or to the information's suitability for any use. NERC/BGS accepts no liability whatever in respect of loss, damage, injury or other occurence however caused. Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced NERC materials "Contains NERC materials ©NERC [year]" English geoscientificInformation 1841 1925-12-31 Microsoft Excel witheld Enquiries British Geological Survey 0115 936 3142 0115 936 3276 The Lyell Centre, Research Avenue South EDINBURGH LOTHIAN EH14 4AP United Kingdom enquiries@bgs.ac.uk distributor Enquiries British Geological Survey 0115 936 3142 0115 936 3276 The Lyell Centre, Research Avenue South EDINBURGH LOTHIAN EH14 4AP United Kingdom enquiries@bgs.ac.uk distributor Enquiries British Geological Survey 0115 936 3143 0115 936 3276 Environmental Science Centre, Nicker Hill, Keyworth NOTTINGHAM NOTTINGHAMSHIRE NG12 5GG United Kingdom enquiries@bgs.ac.uk distributor Enquiries British Geological Survey United Kingdom not available distributor https://webapps.bgs.ac.uk/services/ngdc/accessions/index.html#item189342 WWW:DOWNLOAD-1.0-http--download Data download https://doi.org/10.5285/bc36472c-de05-4981-8c8b-43677ad7f956 WWW:LINK-1.0-http--related Citation Information - Digital Object Identifier (DOI) British Geological Survey, Maume, E., Eaton, E., Macmillan, S., Brown, W. (2025). Monthly magnetic data from the Greenwich Magnetic Observatory Yearbooks (1841 – 1925). NERC EDS National Geoscience Data Centre. (Dataset). https://doi.org/10.5285/bc36472c-de05-4981-8c8b-43677ad7f956 information https://geomag.bgs.ac.uk/data_service/data/yearbooks/grw.html WWW:LINK-1.0-http--link BGS Greenwich Magnetic Observatory Yearbooks & Historical Articles homepage information nonGeographicDataset non geographic dataset INSPIRE Implementing rules laying down technical arrangements for the interoperability and harmonisation of Geology 2011 publication See the referenced specification false Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services 2010-12-08 publication See http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:323:0011:0102:EN:PDF false Historically, a summary of magnetic and meteorological observations from Greenwich Observatory were published in annual yearbooks. This project manually digitised (from digital image scans of the yearbooks) the magnetic observations necessary to reproduce monthly mean values. Units were converted and standardised, documented corrections and baselines were applied where available. Best modern interpretation was tested and applied where original documentation was lacking. Due to the variety of instruments and recording formats used between 1841 and 1925, a variety of methodologies were used to calculate and validate the monthly mean data. Monthly mean data, and the calculations used to derive them are contained in the data set, with full details given in the BGS open report (https://nora.nerc.ac.uk/id/eprint/536965/).