RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 10, ES4003, doi:10.2205/2007ES000258, 2008
[44] 1. The results of our work have indicated that the situation with the Earth's magnetic field is now extremely unfavorable for Russia - the main magnetic field here subsides several times more rapidly than on the entire planet. In the USA, for example, the full strength of the magnetic field has increased over the same period of time. Noteworthy that the local alterations of the main magnetic field over 5 years exceed considerably the average values for the whole Earth. Moreover, the average weakening of the main field in Russia (especially of its full and vertical components) several times exceeds the one for the Earth. It could be assumed that against the background of subsiding of the main dipole the relative role of multipoles of higher order is getting stronger, entailing the considerable impact of the relative role of local deviations of the magnetic field. Let us note that the process of subsiding of the main dipole against the background of insignificantly changing multipoles can lead to a considerably more rapid deterioration of orientation of the local magnetic navigation systems (due to the growing role of local deviations of the field's strength), than if the field was presented by the main dipole only. For solving these tasks the main magnetic dipole acts like a specific "signal'', and multipoles as "noises'', when changing of the "signal/noise'' ratio is more important than the change of a signal's absolute level.
[45] 2. It was established that the horizontal component of the vector of strength of the Earth's main field has 4 extrema: three minima (two of them are the Earth's magnetic poles, the third, the local minimum, is located near the southern end of Africa - |H| = 10,410 nT) and the local maximum ( |H| = 41,380 nT), located near Singapore, intersected by the magnetic equator - the area, where strong earthquakes have been the most frequent over the last time. The last two extrema are related to the non-dipole field.
[46] 3. The technology of elaboration of the geographical map, the adopted system of coordinates, altitudes and legend have provided the opportunity to display the entire structure of the Earth's main magnetic field according to the scale 1:25,000,000 and analyze the tendencies of its change.
[47] 4. The geographical map was elaborated, that can be used in scientific research and practical work. It will help to solve various tasks of prediction, related to the weather, navigation, based on magnetometry, quality of the people life and study of other physical fields of the Earth. Time series of 1995-2005 are insufficient for a well-founded prediction of changes of the magnetic field for the next decades. It is still difficult to establish, whether these negative tendencies grow or reach its maximum. For the corresponding analysis and making conclusions it is necessary to use the data from 1900 up to the present time. If the pace of the described changes of the main magnetic field continue to grow in Russia and in the CIS countries, then in the next decades significant problems, can arouse related to the national navigation, based on magnetometry.
[48] 5. The work fulfilled and results obtained were applied in the Defense Ministry of Russia and in Rosgidromet and also were reported at the Scientific Council on geoinformatics of the presidium RAS. The examined directions of research are completely in line with the program of RAS "Electronic Earth'', and the results are included into the list of completed projects of this program.
[49] 6. The results of data analysis on the direction and change of strength of the magnetic field are of tremendous practical importance, especially for Russia, because navigation in this country (in contrast to the USA) is mainly related to the use of vector and value of strength of the magnetic field. Given the diverse character of changes of the field's strength in many areas of the Earth, calculations in reference points, analogical to the carried out analysis, are necessary. The number of these points is 1768. Thus the future research will require considerably more efforts and time, including preparing special programs of calculation and presentation of results of the data analysis of the Earth' magnetic field.
[50] 7. The results, obtained during the carried out research are intended to be used at elaborating the federal Atlas of the main magnetic field of the Earth.
Citation: 2008), Chart-making of the Earth's main magnetic field, Russ. J. Earth Sci., 10, ES4003, doi:10.2205/2007ES000258.
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