The data of observations since 1951 in the upper part of the Southern Bug River basin in the west of Ukraine are analyzed. The results indicate that the climate change occurring on Earth disrupts the regular cyclicity of groundwater flow indicators. The identified 7–8-year groundwater level and flow to the river cyclicity correlates well with the air temperature, precipitation and river runoff cyclicity. The noted groundwater cyclicity appears with some delay after the establishment of the 8-year air temperature cyclicity observed since 1969. The manifestation of a 7–8-year cycle depends on the groundwater table (GWT) depth. For shallow groundwater (1.0–2.5 m), such rhythms have been observed since 1975, and for deeper levels, since 1989, which is recognized as the year of the beginning of the climate changes. Moreover, 7–8-year rhythms in the fluctuation of groundwater parameters are characteristic of mainly high-water periods of their multiyear regime, and during the low-flow phase is significantly weakened. During 2011–2014, the groundwater levels abnormally decreased and the 8-year cycles were replaced with 5-year ones. The influence of air temperature on the groundwater regime exceeds the role of other factors. Wavelet analysis was used as the main method of periodicity observation. Gaussian and Morlet wavelets provide the visualization of pronounced periodicities of data. Using multiple correlation analysis, it was confirmed that temperature has become the dominant impact factor on the groundwater (GWT 1.5–4.0 m) regime in recent decades.

Cluster decay, as a special type of radioactive decay, up to date, is widely investigated. Nevertheless, until now, this activity is restricted: from one side by the possibilities of theoretical analysis, where some suc-cess is obtained for light nuclei only; and from another side only by experiments for nuclei defragmentation in searching for fission on magic nuclei. However, standard methods of radiometry and statistical analysis have not yet been applied. Such possibility can be realized by searching for acts of cluster decay as a rare event on an array of alpha decay acts of actinides, which are recorded by industrial ionization fission chambers. The scheme of the experiment is discussed, which consists in the registration of every act of alpha decay, against the back-ground of which it is possible to detect the presence of nuclear clusters based on isotopes of $^{12,14}$C, $^{20}$O, and others, which can be formed in the decay of $^{234,235}$U. The requirements for electronics and the background con-ditions for such an experiment are discussed in detail.

Analysis of a long-term regular series of measurements of signals from the automated system of radiation control (ASRC) in the Chornobyl exclusion zone revealed many features, which are reproduced for different observation posts and which we will try to consider from the general position of the influence of cosmic factors. It is implied that these features are clearly linked to certain astronomical phenomena. It is possible to propose a model that describes all these phenomena, namely the possibility of manifestations of the influence of cosmic rays. Such a mechanism as a cause of changes in radioactive background signals in general and in ASRC signals, in particular, has not been considered previously. Probably because its contribution was considered small.