Regional Characteristics of Geomagnetic Activity: Comparative Analysis of Local K and Global Kp Indices
Kapytin V. Andreyev A. Somsikov V. Zhumabayev B. Mukasheva S. Chsherbulova Y. Utebayev S.
December 2025Multidisciplinary Digital Publishing Institute (MDPI)
Atmosphere
2025#16Issue 12
Geomagnetic activity reflects the complex coupling between the solar wind, magneto-sphere and ionosphere. While the global Kp index serves as a standard proxy for geo-magnetic disturbances, it obscures regional variations linked to local current systems and ionospheric conductivity. This study investigates regional features of geomagnetic activity using the local K index from the Almaty (AAA) observatory and compares its temporal dynamics with Kp for 2007–2025. A combination of statistical, spectral, wavelet, and nonlinear methods was applied, including power spectral density, continuous and cross-wavelet transforms, multifractal detrended fluctuation analysis, and permutation entropy. These approaches capture both linear and nonlinear features of variability and reveal scale-dependent structures in geomagnetic fluctuations. The results show a high correlation (r ≈ 0.84) between K (AAA) and Kp, but with a consistent positive offset of the local index, indicating sensitivity to regional ionospheric processes. Wavelet coherence highlights strong coupling in the 13–27-day band associated with solar rotation. Multifractal spectra reveal broader, more heterogeneous scaling in Kp and narrower, more intermittent dynamics in K during disturbed periods. Local indices, like K (AAA), thus provide essential insight into mid-latitude electrodynamics, complementing global measures in characterizing the nonlinear spatio-temporal complexity of geomagnetic activity.
cross-wavelet transform , geomagnetic activity , K index , Kp index , multifractal detrended fluctuation analysis , permutation entropy , power spectral density , solar-terrestrial coupling , wavelet coherence
Text of the article Перейти на текст статьи
Ionosphere Institute, Almaty, 050020, Kazakhstan
Faculty of Physics and Technology, Al-Farabi Kazakh National University, Almaty, 050040, Kazakhstan
Ionosphere Institute
Faculty of Physics and Technology
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026