Skip to main content

Local time features of geomagnetic jerks

Abstract

The geomagnetic jerk amplitudes, which are defined as abruptness of changes in the trends of geomagnetic time series, are investigated with geomagnetic monthly means computed from hourly mean values at each local time. A statistical time series model in which the trend component is expressed by a second order spline function with variable knots is constructed for each time series. The optimum parameter values of the model including positions of knots are estimated by the maximum likelihood method, and the optimum number of parameters including the number of knots are determined based on the Akaike Information Criterion (AIC). The jerks are detected objectively and automatically by regarding the optimized positions of knots as the occurrence epochs. This analysis reveals that the spatial distributions of jerk amplitudes essentially do not depend on the local time, which indicates that the jerks cannot be explained by abrupt changes in intensities of latitudinally flowing external currents such as the field-aligned currents. Longitudinally flowing currents, on the other hand, such as the ring current could explain the distributions. The abrupt changes of the ring current intensity are estimated from the distributions of jerk amplitudes in the eastward component in 1969, 1978, and 1991 supposing that an abrupt change in the ring current intensity causes a jerk. However those estimated changes cannot consistently explain the distributions of the jerks in the northward and downward components. Therefore it is plausible that the jerks which occurred in 1969, 1978, and 1991 are not caused by external sources but internal ones. It is also confirmed that the occurrence epochs of jerks in the southern hemisphere are a few years after those of the 1969 and 1978 jerks in the northern hemisphere, and it is also found that the jerk in the southern hemisphere occurred a few years after the occurrence of the 1991 jerk in Europe. Taking these time lags in occurrence epochs into account, it can be said that the 1969, 1978, and 1991 jerks are global phenomena.

References

  • Achache, J., V. Courtillot, J. Ducruix, and J.-L. Le Mouël, The late 1960s secular variation impulse: further constraints on deep mantle conductivity, Phys. Earth Planet. Int., 23, 72–75, 1980.

    Article  Google Scholar 

  • Alexandrescu, M., D. Gibert, G. Hulot, J.-L. Le Mouël, and G. Saracco, Detection of geomagnetic jerks using wavelet analysis, J. Geophys. Res., 100, 12557–12572, 1995.

    Article  Google Scholar 

  • Alexandrescu, M., D. Gibert, G. Hulot, J.-L. Le Mouël, and G. Saracco, Worldwide wavelet analysis of geomagnetic jerks, J. Geophys. Res., 101, 21975–21994, 1996.

    Article  Google Scholar 

  • Alldredge, L. R., A discussion of impulses and jerks in the geomagnetic field, J. Geophys. Res., 89, 4403–4412, 1984.

    Article  Google Scholar 

  • Alldredge, L. R., More on the alleged 1970 geomagnetic jerk, Phys. Earth Planet. Int., 39, 255–264, 1985.

    Article  Google Scholar 

  • Anderson, B. D. O. and J. B. Moore, Optimal Filtering, Prentice-Hall, 1979.

  • Backus, G. E., Application of mantle filter theory to the magnetic jerk of 1969, Geophys. J. R. astr. Soc., 74, 713–746, 1983.

    Google Scholar 

  • Cafarella, L. and A. Meloni, Evidence for a geomagnetic jerk in 1990 across Europe, Annali di Geofisica, XXXVIII, 451–455, 1995.

    Google Scholar 

  • Courtillot, V., J. Ducruix, and J.-L. Le Mouël, Sur une accélération récente de la variation séculaire du champ magnétique terrestre, C. R. Acad. Série D, 1095–1098, 1978.

  • Davis, R. G. and K. A. Whaler, The 1969 geomagnetic impulse and spin-up of the Earth’s liquid core, Phys. Earth Planet. Int., 103, 181–194, 1997.

    Article  Google Scholar 

  • De Michelis, P., L. Cafarella, and A. Meloni, Worldwide character of the 1991 geomagnetic jerk, Geophys. Res. Lett., 25, 377–380, 1998.

    Article  Google Scholar 

  • Ducruix, J., V. Courtillot, and J.-L. Le Mouël, The late 1960s secular variation impulse, the eleven year magnetic variation and the electrical conductivity of the deep mantle, Geophys. J. R. astr. Soc., 61, 73–94, 1980.

    Article  Google Scholar 

  • Gavoret, J., D. Gibert, M. Menvielle, and J.-L. LeMouël, Long-term variations of the external and internal components of the earth’s magnetic field, J. Geophys. Res., 91, 4787–4796, 1986.

    Article  Google Scholar 

  • Golovkov, V. P., T. I. Zvereva, and A. O. Simonyan, Common features and differences between “jerks” of 1947, 1958 and 1969, Geophys. Astrophys. Fluid Dyn., 49, 81–96, 1989.

    Article  Google Scholar 

  • Gubbins, D. and L. Tomlinson, Secular variation from monthly means from Apia and Amberley magnetic observatories, Geophys. J. R. astr. Soc., 86, 603–616, 1986.

    Article  Google Scholar 

  • Higuchi, T. and S. Ohtani, Automatic identification of large-scale field-aligned current structures, J. Geophys. Res., 105, 25305–25315, 2000.

    Article  Google Scholar 

  • Kerridge, D. J. and D. R. Barraclough, Evidence for geomagnetic jerks from 1931 to 1971, Phys. Earth Planet. Int., 39, 228–236, 1985.

    Article  Google Scholar 

  • Kitagawa, G. and W. Gersch, Smoothness priors analysis of time series, Lecture Notes in Statistics, 116, Springer-Verlag, New York, 1996.

    Google Scholar 

  • Le Huy, M., M. Alexandrescu, G. Hulot, and J.-L. Le Mouël, On the characteristics of successive geomagnetic jerks, Earth Planets Space, 50, 723–732, 1998.

    Article  Google Scholar 

  • Le Huy, M., M. Mandea, J.-L. Le Mouël, and A. Pais, Time evolution of the field flow at the top of the core. Geomagnetic jerks, Earth Planets Space, 52, 163–173, 2000.

    Article  Google Scholar 

  • Le Mouël, J.-L. and V. Courtillot, Core motions, electromagnetic core-mantle coupling and variations in the earth’s rotation: new constraints from geomagnetic secular variation impulses, Phys. Earth Planet. Int., 24, 236–241, 1981.

    Article  Google Scholar 

  • Le Mouël, J.-L., J. Ducruix, and C. H. Duyen, The worldwide character of the 1969–1970 impulse of the secular acceleration rate, Phys. Earth Planet. Int., 28, 337–350, 1982.

    Article  Google Scholar 

  • Macmillan, S., A geomagnetic jerk for the early 1990s, Earth Planet. Sci. Lett., 137, 189–192, 1996.

    Article  Google Scholar 

  • Malin, S. R. C. and B. M. Hodder, Was the 1970 geomagnetic jerk of internal or external origin?, Nature, 296, 726–728, 1982.

    Article  Google Scholar 

  • Mandea Alexandrescu, M., D. Gibert, J.-L. Le Mouël, G. Hulot, and G. Saracco, An estimate of average lower mantle conductivity by wavelet analysis of geomagnetic jerks, J. Geophys. Res., 104, 17735–17745, 1999.

    Article  Google Scholar 

  • Mandea, M., E. Bellanger, and J.-L. Le Mouël, A geomagnetic jerk for the end of the 20th century?, Earth Planet. Sci. Lett., 183, 369–373

    Article  Google Scholar 

  • McLeod, M. G., On the geomagnetic jerk of 1969, J. Geophys. Res., 90, 4597–4610, 1985.

    Article  Google Scholar 

  • McLeod, M. G., Signals and noise in magnetic observatory annual means: mantle conductivity and jerks, J. Geophys. Res., 97, 17261–17290, 1992.

    Article  Google Scholar 

  • Nevanlinna, H. and C. Sucksdorff, Impulse in global geomagnetic “secular variation”, 1977–1979, J. Geophys., 50, 68–69, 1981.

    Google Scholar 

  • Press, W. H., B. P. Flannery, S. A. Teukolsky, and W. T. Vetterling, Numerical Recipes: The Art of Scientific Computing, Cambridge University Press, 1986.

  • Stewart, D. N. and K. A. Whaler, Optimal piecewise regression analysis and its application to geomagnetic time series, Geophys. J. Int., 121, 710–724, 1995.

    Article  Google Scholar 

  • Thompson, D. and J. C. Cain, The geomagnetic jerk of 1969 and the DGRFs, Phys. Earth Planet. Int., 48, 386–388, 1987.

    Article  Google Scholar 

  • Whaler, K. A., A new method for analysing geomagnetic impulses, Phys. Earth Planet. Int., 48, 221–240, 1987.

    Article  Google Scholar 

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to Hiromichi Nagao.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Nagao, H., Iyemori, T., Higuchi, T. et al. Local time features of geomagnetic jerks. Earth Planet Sp 54, 119–131 (2002). https://doi.org/10.1186/BF03351712

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1186/BF03351712

Keywords

  • Local Time
  • Occurrence Rate
  • Secular Variation
  • Trend Component
  • Geomagnetic Jerk