scholarly journals Morphology of the southern African geomagnetic field derived from observatory and repeat station survey observations: 2005–2014

2016 ◽  
Vol 68 (1) ◽  
Author(s):  
P. B. Kotzé ◽  
M. Korte
Keyword(s):  
Geomagnetic Field ◽  
Repeat Station

scholarly journals Repeat-station surveys: implications from chaos and ergodicity of the recent geomagnetic field

2013 ◽  
Vol 56 (1) ◽  
Author(s):  
Angelo De Santis ◽  
Enkelejda Qamili ◽  
Gianfranco Cianchini
Keyword(s):  
Time Series ◽  
Phase Space ◽  
Time Domain ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Repeat Station ◽  
Reconstructed Phase Space ◽  
Time Averages ◽  
The Time Domain ◽  
Strong Necessity

<p>The present geomagnetic field is chaotic and ergodic: chaotic because it can no longer be predicted beyond around 6 years; and ergodic in the sense that time averages correspond to phase-space averages. These properties have already been deduced from complex analyses of observatory time series in a reconstructed phase space and from global predicted and definitive models of differences in the time domain. These results imply that there is a strong necessity to make repeat-station magnetic surveys more frequently than every 5 years. This, in turn, will also improve the geomagnetic field secular variation models. This report provides practical examples and case studies.</p><p> </p>

How Accurate Geomagnetic Regional Modeling Using Ordinary Kriging For Clustered Distributed Data?: New Insight From Indonesian Archipelago

2021 ◽  
Author(s):  
Muhamad Syirojudin ◽  
Eko Haryono ◽  
Suaidi Ahadi
Keyword(s):  
Geomagnetic Field ◽  
Ordinary Kriging ◽  
Distributed Data ◽  
Geostatistical Modeling ◽  
Kriging Method ◽  
Spherical Cap ◽  
Repeat Station ◽  
Indonesian Archipelago ◽  
Typical Data ◽  
Spherical Cap Harmonic Analysis

Abstract Indonesia relies only on the limited number of repeat station networks due to the archipelago setting with the extensive sea with the clustery distributed pattern. This paper explored geostatistical modeling to overcome that typical data characteristic. The modeling used repeat station data from the 1985 to 2015 epoch. The research used ordinary kriging (OK) compared to the Spherical Cap Harmonic Analysis (SCHA) and Polynomial. The results show that the root means square error (RMSE) of each declination, inclination, and total intensity vary among epochs. OK method for declination component produces smaller average RMSE (7.67 minutes) than SCHA (9.26 minutes) and Polynomial (7.97minutes). For the inclination component, OK has an average RMSE of 9.55 minutes, smaller than SCHA (10.05) but slightly higher than Polynomial (9.36 minutes). For the total intensity component, OK produce an average RMSE of 63.58 nT, smaller than SCHA (82.24 nT) and Polynomial (68.97 nT). The finding shows that the kriging method can be a promising method to model the regional geomagnetic field, especially in the area of limited available data and clustered distributed data.

scholarly journals Preface

2013 ◽  
Vol 55 (6) ◽  
Author(s):  
Paola De Michelis ◽  
Gerald Duma
Keyword(s):  
Geomagnetic Field ◽  
Regional Scale ◽  
Level Of Detail ◽  
European Countries ◽  
European Continent ◽  
Repeat Station ◽  
Secular Variations ◽  
Long Time ◽  
The Individual

<p>Repeat station measurements are designed specifically to represent and model the geomagnetic field and its secular variations on a regional scale with a level of detail that would not be achievable using only data from permanent geomagnetic observatories. Although geomagnetic repeat station surveys have a long tradition in many European countries, they were carried out independently in the individual countries. For this reason, it has been difficult for a long time to use the data efficiently for studies of geomagnetic secular variations of the whole European continent. […]</p>

First Results of the 2019 Algerian Magnetic Repeat Station Network

2020 ◽  
Author(s):  
Abdenacuer Lemgharbi ◽  
Abdeslam Abtout ◽  
Mohamed Hamoudi ◽  
Abdelhamid Bendekken ◽  
Fatma Annad ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Station Network ◽  
Repeat Station ◽  
First Results ◽  
Geomagnetic Field Models ◽  
Polynomial Modeling ◽  
History Of ◽  
Absolute Measurements

&lt;p&gt;&lt;strong&gt;Abstract:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;The second part of the history of the Algerian magnetic repeat station network goes back to 1989 when the new one was started with 37 stations. It was then followed by three other networks in 1993, 1997 and 2005. The first part of this history started at the beginning of the XX&lt;sup&gt;th&lt;/sup&gt; and ended ca 1956.&lt;/p&gt;&lt;p&gt;After a 14-year break, we launched a new repeat stations network in February 2019. The number of carried out stations was increased to 51 to try to cover all the territory.&lt;/p&gt;&lt;p&gt;Each repeat station network consists of stations of periodically, say &amp;#160;5-6 years, measured of three components of the Earth's magnetic field. to try to derive the spatial distribution of the geomagnetic field of Algeria and it's secular variation. This periodicity is also very important for the need to update local as well as global geomagnetic field models such as the International Geomagnetic Reference Field (IGRF).&lt;/p&gt;&lt;p&gt;In this work we describe the new 2019 Algerian repeat station network. Then we will discuss the steps of the absolute measurements using two methods. The first one is called the &amp;#8216;method of zero&amp;#8217; and the second one &amp;#8216;method of residuals&amp;#8217;. The accuracy and resolution of the instruments and data reduction used and their effect on the final results will as well be discussed. We derive the spatial distribution of the geomagnetic field, and its secular variation. Finally, we will show how local, for instance regional polynomial modeling, is the key issue.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Key words&lt;/strong&gt;: geomagnetic repeat network, absolute measurements, zero method, residual method, magnetic maps of Algeria, secular variation.&lt;/p&gt;

scholarly journals Ukrainian geomagnetic repeat station network and results of the field work reduced to the epoch 2005.5

2013 ◽  
Vol 55 (6) ◽  
Author(s):  
Valentyn Maksymchuk ◽  
Myxailo Orlyuk ◽  
Viktor Tregybenko ◽  
Yurij Horodyskyy ◽  
Dmytro Marchenko
Keyword(s):  
Geomagnetic Field ◽  
Field Work ◽  
Station Network ◽  
Repeat Station ◽  
Geodetic Measurements ◽  
Magnetic Declination

<p>The results of geomagnetic field components of the renewed Ukrainian repeat stations (RS) network are presented. The methods of absolute geomagnetic and astro-geodetic measurements are described. The reduction of geomagnetic field components is carried out to the 2005.5 epoch and a catalogue of RS is created. Maps of magnetic declination for the Ukraine are constructed and compared with results calculated by the IGRF-2005 model.</p><p> </p>

Models of the geomagnetic field and characteristics of magnetic storms

2006 ◽  
Vol 12 (1) ◽  
pp. 64-69
Author(s):  
O.I. Maksimenko ◽  
◽  
L.N. Yaremenko ◽  
O.Ya. Shenderovskaya ◽  
G.V. Melnyk ◽  
...  
Keyword(s):  
Geomagnetic Field ◽  
Magnetic Storms

MicroVolt Variations of The Human Brain (Quantitative Electroencephalography) Display Differential Torque Effects During West-East versus North-South Orientation in the Geomagnetic Field

2016 ◽  
Vol 12 (2) ◽  
pp. 4255-4259
Author(s):  
Michael A Persinger ◽  
David A Vares ◽  
Paula L Corradini
Keyword(s):  
Human Brain ◽  
Geomagnetic Field ◽  
Neuronal Cell ◽  
Single Subject ◽  
Additional Energy ◽  
Actual Measurement ◽  
Neuronal Processes ◽  
Basic Physics ◽  
Order Of Magnitude ◽  
The Moment

                The human brain was assumed to be an elliptical electric dipole. Repeated quantitative electroencephalographic measurements over several weeks were completed for a single subject who sat in either a magnetic eastward or magnetic southward direction. The predicted potential difference equivalence for the torque while facing perpendicular (west-to-east) to the northward component of the geomagnetic field (relative to facing south) was 4 μV. The actual measurement was 10 μV. The oscillation frequency around the central equilibrium based upon the summed units of neuronal processes within the cerebral cortices for the moment of inertia was 1 to 2 ms which are the boundaries for the action potential of axons and the latencies for diffusion of neurotransmitters. The calculated additional energy available to each neuron within the human cerebrum during the torque condition was ~10-20 J which is the same order of magnitude as the energy associated with action potentials, resting membrane potentials, and ligand-receptor binding. It is also the basic energy at the level of the neuronal cell membrane that originates from gravitational forces upon a single cell and the local expression of the uniaxial magnetic anisotropic constant for ferritin which occurs in the brain. These results indicate that the more complex electrophysiological functions that are strongly correlated with cognitive and related human properties can be described by basic physics and may respond to specific geomagnetic spatial orientation.

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