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oa Seven-year cyclicity manifestations in groundwater mode revealed by wavelet analysi
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Geoinformatics: Theoretical and Applied Aspects 2020, May 2020, Volume 2020, p.1 - 5
Abstract
Statistical methods, mainly wavelet analysis, showed the presence of 7–8 -year cycles of levels and runoff of groundwater in the Pivdennyi Bug river basin. These rhythms have been manifesting since 1989, which is the year of the beginning of significant climate change in Ukraine. These rhythms largely correspond to the rhythms of precipitation (8.7 years), river runoff and especially rhythms of temperature (8 years). It is also important that the cyclicity of 7–8 years in the GWL mode is practically not affected by local factors (degree of regulation, lithology, depth of the GWL, distance from the river, etc.), which significantly influence the rhythms of other periodicity. Instead, more regular cycles of 10–11 years, corresponding to the rhythms of solar activity, are almost non-existent after 1986. However, after 2003–2006, the daily GWL rhythm of 7–8 years (7.9 ± 0.6) also becomes irregular, which may be due to a new rotating meteorological phenomenon, which can lead to irreversible changes in the groundwater balance.