Soil temperature regimes in the discontinuous permafrost zone in the east European Russian arctic

Temperature regimes of eleven plots with tundra soils were studied in the northeastern part of European Russia within the discontinuous permafrost zone. The duration of soil temperature records ranged from 1 to 9 years. The selected plots were representative of the diversity of landscape and soil conditions in the study area. Virgin tundra soils, a cultivated soil under sown grassland, and soils of secondary biocenoses that developed in place of the former sown grasslands were studied. It was shown that the winter and mean annual temperatures in the permafrost-affected soils drastically differ from those in the soils without permafrost, though the summer temperatures in the root zone of both soil groups are relatively similar. The soil temperature regimes were classified according to Russian (Dimo, 1972) and American (Soil Taxonomy, 1999) classification systems. The degree of detail provided by the Russian system proved to be somewhat greater; at the same time, in contrast to the American system, it does not make it possible to distinguish the soils with warm permafrost in the discontinuous permafrost zone from the soils without permafrost at all.