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Secular Variation Across the Oceans: a Retrospective Study from 35 Years of Shipboard Total Field Measurements in the NE AtlanticThis is a pilot study to determine whether secular variation information can be retrieved from underway shipboard total field measurements with sufficient accuracy to complement geomagnetic data from land-based observatories. Applying the various new techniques described in this report, we extracted values of the total field at 42,677 crossovers or ship track intersection points contained in data sets collected between 18 degrees N and 50 degress N in the NE Atlantic, and extending temporally from 1955 to 1990. We used an edited subset of these total field values to derive the secular variation at 30,140 different locations in the study area, and compared the results with DGRF secular variation over the study area, calculated at 5 year intervals. The derived and DGRF values agree well, showing that indeed marine data can be a source for secular variations. However the analysis demonstrated that due to inherent noise in the marine data, only minor improvements on the DGRF values for the secular variation can be achieved.
Document ID
19920019384
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Williams, C. A.
(Cambridge Univ. (England). Dartmouth, Nova Scotia , Canada)
Verhoef, J.
(Geological Survey of Canada Dartmouth, Nova Scotia , Canada)
Macnab, R.
(Geological Survey of Canada)
Date Acquired
September 6, 2013
Publication Date
June 1, 1992
Publication Information
Publication: NASA. Goddard Space Flight Center, Types and Characteristics of Data for Geomagnetic Field Modeling
Subject Category
Geophysics
Accession Number
92N28627
Funding Number(s)
CONTRACT_GRANT: NERC-GR3/7704
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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