Open AccessGeomagnetic secular acceleration
Author(s) -
Barraclough D. R.,
Malin S. R. C.
Publication year - 1979
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1979.tb04807.x
Subject(s) - secular variation , geodesy , earth's magnetic field , acceleration , epoch (astronomy) , observatory , geology , geophysics , physics , magnetic field , astronomy , classical mechanics , stars , quantum mechanics
Summary. A spherical harmonic model of the second time‐derivative of the geomagnetic field is determined, for the first time, directly from measures of the secular acceleration based on observatory annual mean data. The data span the interval 1964.5–1975.5, and 165 observatories are included. The model comprises the 32 coefficients of degree and order up to 6 that are significant at the 5 per cent level. Its primary purpose is to aid in the reduction of data to epoch for the 1980 series of navigational charts. The model is compared with earlier estimates of secular acceleration, derived by less direct methods.