Monthly magnetic data from the Greenwich Magnetic Observatory Yearbooks (1841 – 1925)

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/

Date (Creation): 2025-08-06

Citation identifier: http://data.bgs.ac.uk/id/dataHolding/13608490

Point of contact

Organisation name	Individual name	Electronic mail address	Role
British Geological Survey	Enquiries	enquiries@bgs.ac.uk	Distributor
British Geological Survey	Enquiries	enquiries@bgs.ac.uk	Distributor
British Geological Survey	Enquiries	enquiries@bgs.ac.uk	Originator
British Geological Survey	Enquiries	enquiries@bgs.ac.uk	Originator
British Geological Survey	Enquiries	enquiries@bgs.ac.uk	Distributor
British Geological Survey	Enquiries	enquiries@bgs.ac.uk	Originator
British Geological Survey	Enquiries	not available	Distributor
British Geological Survey	Enquiries	not available	Point of contact

Maintenance and update frequency: notApplicable

GEMET - INSPIRE themes, version 1.0

Geology

BGS Thesaurus of Geosciences

NGDC Deposited Data
Citable Data
Geomagnetism
Geophysics

dataCentre

Keywords

NERC_DDC

Access constraints: Other restrictions

Other constraints: licenceOGL

Other constraints: Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced NERC materials "Contains NERC materials ©NERC [year]"

Use constraints: Other restrictions

Other constraints: 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.

Other constraints: Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced NERC materials "Contains NERC materials ©NERC [year]"

Language: English

Topic category

Geoscientific information

Begin date: 1841

End date: 1925-12-31

Reference System Information

No information provided.

Distribution format

Name	Version
Microsoft Excel	witheld

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
British Geological Survey	Enquiries	enquiries@bgs.ac.uk	Distributor

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
British Geological Survey	Enquiries	enquiries@bgs.ac.uk	Distributor

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
British Geological Survey	Enquiries	enquiries@bgs.ac.uk	Distributor

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
British Geological Survey	Enquiries	not available	Distributor

OnLine resource

Protocol	Linkage	Name
WWW:DOWNLOAD-1.0-http--download	https://webapps.bgs.ac.uk/services/ngdc/accessions/index.html#item189342	Data

OnLine resource

Protocol	Linkage	Name
WWW:LINK-1.0-http--related	https://doi.org/10.5285/bc36472c-de05-4981-8c8b-43677ad7f956	Citation Information - Digital Object Identifier (DOI)

OnLine resource

Protocol	Linkage	Name
WWW:LINK-1.0-http--link	https://geomag.bgs.ac.uk/data_service/data/yearbooks/grw.html	BGS Greenwich Magnetic Observatory Yearbooks & Historical Articles homepage

Hierarchy level: Non geographic dataset

Other: non geographic dataset

Conformance result

Title: INSPIRE Implementing rules laying down technical arrangements for the interoperability and harmonisation of Geology

Date (Publication): 2011

Explanation: See the referenced specification

Pass: No

Conformance result

Title: 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

Date (Publication): 2010-12-08

Explanation: See http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:323:0011:0102:EN:PDF

Pass: No

Statement: 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/).