On the Geomagnetic Variations Observed on the Earth's Surface in the Period Range of Planetary Waves

摘要

The spectra of geomagnetic variations calculated in the period range close to planetary waves-5, 10, and 16 days-are analyzed. The records of the geomagnetic field at the Geophysical Observatory "Mikhnevo" of the Institute of Geosphere Dynamics of Russian Academy of Sciences are used. Spectral estimation based on parametric approach is carried out for the winter and summer periods of 2009 (low solar activity) and 2015 (high solar activity). For the first time, it is established that the harmonics directly related to the manifestation of the atmospheric planetary waves in the entire period range from 4 to 17 days are only observed in winter and, irrespective of solar activity; the changes in the atmospheric pressure are about a month ahead of the changes in the geomagnetic field. In the spectra of geomagnetic variations in the period range of 4-17 days, the harmonics of the 27-day geomagnetic periodicity and the harmonics associated with their modulation by the 11-year solar cycle, annual and semiannual variations are revealed. In the spectra for the period range from 12 to 17 days, harmonics with periods close to tidal waves M-f and M-sf are identified.