In cold bio-climatic latitudes, the cycles of matter and energy, which make up a soil formation process, are conditioned by the duration of the frozen and thawed state of the Earth surface, the character of seasonal freezing and thawing, and the depth of these processes in cryosols (connected with the summer thawing layer in permafrost areas) or seasonally frozen soils (found in the layer of winter freezing beyond permafrost regions).
We have considered the spatial and temporal regularities of the temperatures distribution in the cryosols and seasonally frozen soils. Together they are an independent natural object - active layer, where an annual cycles of long (6-8 months) and deep (to 4 m) seasonal freezing/thawing is a leading process which determines the existence of a peculiar group of soils. Geocryology and Soil Science in such a case have one and the same object of investigations and for its study the achievements of both disciplines are combined.
The cryosols and seasonally frozen soils temperature regimes were studied by over 300 standard state meteorological stations, mostly in Russia. Regular measurements on some of them were started at 1890, and the data covered almost 100 years. The observations includes several levels from soil surface to 3.2 m depth and represent by monthly and annual data: a) the first/last frost and minimal, maximal and average temperatures at the soil surface; b) the first/last frost, as well as average temperatures at the depths; c) the number of days with temperatures < 0 oC and the depths of this isotherm penetration; d) the depths and rates of freezing/thawing.
The data base also contain the similar information from Scandinavia, North America, China and republics of former USSR. The results collected are unique by period covered, territory, natural zones, type of seasonally frozen or thawed soils, wide spectrum of ecological and geographical conditions from Polar to arid deserts and Northern lowlands to Central Asia mountains. The potential scientific significance of collection is hard to overestimate. It will stimulate numerous studies in Soil Physics and Climatology. However, the main progress could be made in soil classification and Global Change aspect.
Results shows, the trends of air temperature fluctuations not necessary means the same trends for soil climate, and not only because the important role of snow and vegetation covers. The main regulators are the soil physical properties and water-ice phase transfers due the processes of freezing and thawing. The Global trend of the Earth responsibility instead of temporal fluctuations of air temperatures should be recorded by the trends of only soil temperature regimes. And because the cryogenic factor compensate the influence of possible additional heat coming, they are different in different regions, on different depths and at different periods of observations. At least, don't demonstrate the Global Warming trend, only well known rhythms.
These computer studies were performed in close cooperation with International Permafrost Association, US Soil Survey, Word Date Center Glaciology; have queries, statistics, graphical and data output; and placed on the Internet server with remote access. Using these data we have the possibility to forecast the resistance of geocryological conditions in soils of both permafrost and active seasonally freezing areas in the case of Global Climate Changes. Also, because there is no general opinion about nomenclature of these frost affected soils, we can to advance the progress in classification by their thermal regimes, which determines the soil forming process. This is the background of their difference from analogous soils in various thermal zones belong to one family but differ from other at the level of types.
David A. Gilichinsky, PhD Laboratory for Soil Cryology Institute of Soil Science & Photosyntesis Russian Academy of Sciences 142292, Pushchino, Moscow Region, RUSSIA Telephone: 7-096-77-32604 Fax: 7-096-77-90532 E-mail: gilichin@issp.serpukhov.su