Abstract
Long-term changes in the magnetic environment of the Earth are of interest to those studying space weather and climate change, particularly in the upper atmosphere. In this paper we examine long-term changes in daily variation as derived from hourly mean values from 14 geomagnetic observatories around the world. Their time series date back to the beginning of the 20th century. We find that there are similar features in all the records, with peaks in the amplitudes of the daily variation occurring in the 1950s and 1980s, and a small upward trend of 1.3 nT/century corresponding to an increase of over 10%. The extrema coincide with those seen in solar irradiance proxy data, in particular the F10.7 flux density dataset which starts in 1947.
Article PDF
Similar content being viewed by others
References
Chapman, S. and J. Bartels, Geomagnetism, Vol. I, Oxford University Press, 1940.
Chulliat, A., E. Blanter, J.-L. Le Mouël, and M. Shnirman, On the seasonal asymmetry of the diurnal and semidiurnal geomagnetic variations, J. Geophys. Res., 110, A05301, doi: 10.1029/2004JA010551, 2005.
Clilverd, M. A., T. D. G. Clark, E. Clarke, and H. Rishbeth, Increased magnetic storm activity from 1868 to 1995, J. Atmos. Solar-Terr. Phys., 60(10), 1047–1056, 1998.
Clilverd, M. A., E. Clarke, T. Ulrich, J. Linthe, and H. Rishbeth, Reconstructing the long-term aa index, J. Geophys. Res., 110, A07205, doi:10.1029/2004JA010762, 2005.
Gustafsson, G., N. E. Papitashvili, and V. O. Papitashvili, A revised corrected geomagnetic coordinate system for Epochs 1985 and 1990, J. Atmos. Terr. Phys., 54, 1609–1631, 1992.
International Association of Geomagnetism and Aeronomy (IAGA), Division V, Working Group VMOD: Geomagnetic Field Modeling, The 10th-Generation International Geomagnetic Reference Field, Geophys. J. Int., 161(3), 561–565, 2005.
Jackson, A., A. R. T. Jonkers, and M. R. Walker, Four centuries of geomagnetic secular variation from historical records, Phil. Trans. R. Soc. Lond., A, 358, 957–990, 2000.
Laštovička, J. R., A. Akmaev, G. Beig, J. Bremer, and J. T. Emmert, Global change in the upper atmosphere, Science, 314, 1253–1254, 2006.
Le Mouël, J.-L., V. Kossobokov, and V. Courtillot, On long-term variations of simple geomagnetic indices and slow changes in magnetospheric currents: The emergence of anthropogenic global warming after 1990?, Earth Planet. Sci. Lett., 232, 273–286, 2005.
Lockwood, M., R. Stamper, and M. N. Wild, A doubling of the Sun’s coronal magnetic field during the past 100 years, Nature, 399, 437–439, 1999.
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, 2000.
Olsen, N., The solar cycle variability of lunar and solar daily geomagnetic variations, Ann. Geophys., 11, 254–262, 1993.
Stamper, R., M. Lockwood, M. N. Wild, and T. D. G. Clark, Solar causes of the long-term increase in geomagnetic activity, J. Geophys. Res., 104, 28325–28342, 1999.
Svalgaard, L. and E. W. Cliver, The IDV index: Its derivation and use in inferring long-term variations of the interplanetary magnetic field strength, J. Geophys. Res., 110, A12103, doi:10.1029/2005JA011203, 2005.
Tobiska, W. K., T. Woods, F. Eparvier, R. Viereck, L. Floyd, D. Bouwer, G. Rottman, and O. R. White, The SOLAR2000 empirical solar irradiance model and forecast tool, J. Atmos. Solar-Terr. Phys., 62(14), 1233–1250, 2000.
Vogt, J., B. Zieger, A. Stadelmann, K.-H. Glassmeier, T. I. Gombosi, K. C. Hansen, and A. J. Ridley, MHD simulations of quadrupolar paleomagnetospheres, J. Geophys. Res., 109, A12221, doi:10.1029/2003JA010273, 2004.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.
The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.
To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Macmillan, S., Droujinina, A. Long-term trends in geomagnetic daily variation. Earth Planet Sp 59, 391–395 (2007). https://doi.org/10.1186/BF03352699
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1186/BF03352699