Variations of Natural Electrical Potentials in the Cryolithozone, Yakutsk

This paper considers daily, seasonal, and interannual variations of natural potentials at two sites in the cryolithozone at the testing polygon of the Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy of the Siberian Branch of the Russian Academy of Sciences near Yakutsk from autumn 2017 to spring 2021. One site includes a waterlogged area (marsh), and the other is located on a "dry" area. Variations of natural electric potentials during the annual season at the site with the marsh had a significant value of -120 mV/100 m. The maximum variation is observed in spring, during the melting of the snow cover due to a sharp humidification of the top layer of soil. The variation on the "dry" area is less than 40 mV/100 m. The transition from summer to winter values for natural potentials occurs in November. The reverse transition from winter to summer conditions occurs from the last third of April through May. These spring-autumn transitions are caused by the freezing of the top layer of soil thawing under summer conditions and the corresponding changes in the electrical properties of the soil. There is a dependence of the value of natural potentials on the value of precipitation that increases soil humidity and its conductivity.