Dependence of the velocity changes of secular variations on the position of observatory and time
DOI:
https://doi.org/10.24028/gzh.v43i3.236388Keywords:
secular variations, solar activity, geomagnetic activity, magnetosphere and ionosphere sourcesAbstract
According to the data of world observatories net secular variations of geomagnetic fields from internal and outer sources have been studied. Averaged 3-year data have been used for this purpose. Procedure of calculations of secular variations from internal and outer sources according to observatories data has been submitted. 1979 has been chosen as a zero level for accounting secular variations from outer sources because the sign of the large-scale magnetic field has changed this year. It has been shown that the value of secular variations from outer sources is different for different regions and increases with the growth of the latitude of magnetic observatory. Maximal values of secular variations are observed in the northern polar cap as well as at the longitudes of the eastern focus of secular variation. It has been shown that at the DIK, CSS, TIK observatories secular variations have maximal values.
Groups of observatories have been segregated with symmetric and asymmetric changes of secular variation comparing to 1979. Symmetric changes of secular variation during two Hail’s cycles are observed at the observatories in circumpolar area (ALE, NAL, BJN), in auroral and middle latitudes. Maximal asymmetry of secular variation is observed at the observatories GDH, BLC, FCC, as well as at certain subauroral observatories and the regions with raised seismic activity.
Secular variation from outer sources depends on the value of the large scale magnetic field of the Sun. The value of secular variation from the inner sources has been modulated by the outer sources and depends on special features of underlying surfaces of the observatories, induction currents in particular.
References
Akasofu, S.-I., & Chapman, S. (1975). Solar-Terrestrial Physics. Moscow: Mir, 512 p. (in Russian).
Bobrov, M. S. (1981). On the fade out of the magne¬to¬sphere ring current. Geomagnetizm i aero¬no¬miya, 21, 1048—1055 (in Russian).
Gvishiani, A. D., Starostenko, V. I., Sumaruk, Yu. P., Soloviev, A. A., & Legostaeva, O. V. (2015). A decrease in solar and geomagnetic activity from cycle 19 to cycle 24. Geomagnetizm i aero¬no¬miya, 55(3), 314—322 (in Russian).
Kalegaev, V. V., & Makarenkov, Ye. V. (2006). Dynamics of the magnetosphere current systems during magnetic storms different intencities. Geomagnetizm i aeronomiya, 46(5), 604—613 (in Russian).
Orlyuk, M. I., Romenets, A. V., Sumaruk, P. V., Sumaruk, Yu. P., & Sumaruk, T. P. (2012). The spatial-temporal structure of the magne¬tic field of Ukraine’s territory: assessment of the contribution of internal and external sour¬ces. Geofizicheskiy Zhurnal, 34(3), 137—144. https://doi.org/10.24028/gzh.0203-3100.v34i3. 2012.116651 (in Ukrainian).
Orlyuk, M. I., Sumaruk, T. P., Sumaruk, Yu. P., & Romenets, A. A. (2014). Valuation of induction current contribution to the secular variation of geomagnetic field (according to the data of Ukrainian geomagnetic observatories). Geo¬fi¬zi¬cheskiy Zhurnal, 36(2), 111—119. https://doi.org/10.24028/gzh.0203-3100.v36i2.2014.116124 (in Ukrainian).
Sumaruk, P. V., & Sumaruk, T. P. (2018). Secular variations of the geomagnetic field on the lithosphere plates of the Earth. Geofizicheskiy Zhurnal, 40(1), 118—133. https://doi.org/10.24028/gzh.0203-3100.v40i3.2018.137199 (in Ukrainian).
Sumaruk, P. V., & Sumaruk, Yu. P. (1998). On the external sources of the secular variations of the geomagnetic field.). Geofizicheskiy Zhurnal, 20(3), 120—126 (in Ukrainian).
Sumaruk, P. V., Feldstein, Ya. I., & Porchgidze, I. D. (1980). Variations of geomagnetic fields on the geomagnetic poles. Physica Solariterrestr., 12, 70—78.
Sumaruk, T. P., & Sumaruk, P. V. (2018). Peculiarities of the geomagnetic field secular variations at the 20th solar activity cycle. Geofizicheskiy Zhurnal, 40(3), 179—191. https://doi.org/10.24028/gzh.0203-3100.v40i3.2018.137199 (in Ukrainian).
Sumaruk, Yu. P. (2001). Ring magnetosphere current and its asymmetry during great magnetic storm. Geofizicheskiy Zhurnal, 23(2), 96—100 (in Ukrainian).
Sumaruk, Yu. P., & Sumaruk, T. P. (2013). On the contribution of external sources into secular variations of the geomagnetic field. Dopovidi NAN Ukrayiny, 23(2), 96—100. https:// doi.org/10.24028/gzh.0203-3100.v40i1. 2018. 124021 (in Ukrainian).
Shevnin, A. D., Levitin, A. E., Gromova, L. I., Dremukhina, L. A., & Kainara, L. A. (2013). Solar cyclic variations at the magnetic elements of observatory «Moscow». Geomagnetizm i aeronomiya, 49(3), 315—320 (in Russian).
Mead, G. D. (1964). Deformations of geomagnetic field by the solar wind. J. Geophys. Res., 69(7), 1181—1196.
Verbanac, G., Luhr, H., Rother, M., Korte, M., & Mandea, M. (2007). Contributions of the external field to the observatory annual means and a proposal for their corrections. Earth, Planet and Space, 59, 251—257. https://doi.org/10.1186/BF03353102.
Downloads
Published
How to Cite
Issue
Section
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Authors who publish with this journal agree to the following terms:
1. Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
2. Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
3. Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
