Climate of West Siberia during the slowing phase of warming (1986–2015) and prediction of hydro-climatic resources for 2021–2030

The relevance of the study. The most visible affect of the present climate change is the rise of surface air temperature. Regional and local indicators of climate change differ from the global characteristics. Transformation of the hydrological cycle, water balance, river runoff in its turn affects climate processes. In order to predict the response of geosystems and their hydro-climatic resources to climate change it is necessary to have a clear vision of contemporary climate change and its projections for the coming decades in specific geographical localities. The aim of the study is (1) to assess the climate change over West Siberia on the basis of statistical analysis of monthly air temperature and precipitation time series up to 2015, (2) predict the average air temperature and precipitation fields for the 2021-2030, and (3) determine the climate-driven changes in water balance and water flow regime over the study area. The methods used in the study. Analysis and forecasting of spatial and temporal variability of surface air temperature and precipitation rates at meteorological stations in the region are made by statistical methods in the StatSoft STATISTICA package (regression analysis, trend analysis, cluster analysis to classify objects, exponential smoothing and forecasting). The averaged monthly land water balance constituents are determined for the base (1966-1985), current (1986-2015) and forecast (2021-2030) using the method of hydrological and climatical calculations developed by V.S. Mezentsev. The results. It is shown that the modern 30yrs climatic period differs from the previous one in higher energy level (air temperature). Against this background, not only upward but downward temperature trends in some months are observed. The authors have predicted the average temperatures and precipitation rates in a cold season and monthly temperatures and precipitation in a warm season of the year at 31 meteorological stations for 2021-2030. The estimates for the current and forecast periods made it possible to compute the average regime parametres of precipitation, evapotranspiration, runoff and moisture of soil active layer at the meteorological stations located in different lanscape zones and regions of West Siberian plain. The projected increase in temperature and evapotranspiration does not lead to the expected decrease in flow even in the southern dry regions. At the same time, soil moisture in summer will decrease everywher

The first computer model of currents in the Kurai Intermountane Basin, Altai, under release of a glacial-dammed lake

The first 2D computer model of the currents (including circulation currents) inside the glacial dammed Kurai Lake under its release caused by the dam break is simulated in the RMA2 program of the SMS 9.2 modeling system. The hydraulic parameters are calculated for several given water discharges in the transit flow (from 10 to 0.3 million m3/s) of the basin. A consecutive change in the circulation currents during the release of the lake is identified. A comparison of the character of circulation and the calculated fields of the depths and the current velocities in the lake with the orientation of the gravel ranges on the bottom of the Kurai basin allows reconstruction of the hydraulic conditions of possible formation of the giant ripple fields

The relevance of the contemporary landscape-ecological and biogeochemical studies of the Ob floodplain

We have systematized and summarized the results of the Ob River floodplain studies and have shown that the flood and the floodplain influence all the territory of Western Siberia due to the processes happening there. The floodplain at different times was the object of interest of many scientists, but the total level of study of the Ob and the associated ground and the lake network water resources and quality can be generally assessed as low. The waters of the Ob middle course are quite polluted according to bacteria content. It is possible that a significant part oforganic and biogenic substances, microorganisms and some microelements come into the Ob floodplain waters from anthropogenic and natural sources distributed in the watersheds area. The soils of the Ob Riverfloodplain can be considered to be clean andfree ofany chemical pollution. In these soils, the amount of trace elements is small. To study the floodplain changes after a flood the methods of landscape ecology are used, such as the collection and analysis of stock and descriptive materials, literature and maps; the preparation of a series of component and general landscape maps. Nowadays a complex research of the Ob River and the adjacent surface waters is relevant

Seasonal dynamics of organic carbon and metals in thermokarst lakes from the discontinuous permafrost zone of western Siberia

Despite relatively good knowledge of the biogeochemistry of Siberian thermokarst lakes during summer base flow, their seasonal dynamics remains almost unexplored. This work describes the chemical composition of 130 thermokarst lakes ranging in size from a few m2 to several km2, located in the discontinuous permafrost zone. Lakes were sampled during spring flood, just after the ice break (early June), the end of summer (August), the beginning of ice formation (October) and during the full freezing season in winter (February). The lakes larger than 1000m2 did not exhibit any statistically significant control of the lake size on dissolved organic carbon (DOC), the major and trace element concentrations over three major open water seasons. On the annual scale, the majority of dissolved elements including organic carbon increased their concentration from 30 to 500 %, with a statistically significant (p summer>autumn>winter. The ice formation in October included several stages: first, surface layer freezing followed by crack (fissure) formation with unfrozen water from the deeper layers spreading over the ice surface. This water was subsequently frozen and formed layered ice rich in organic matter. As a result, the DOC and metal (Mn, Fe, Ni, Cu, Zn, As, Ba and Pb) concentrations were highest near the surface of the ice column (0 to 20 cm) and decreased by a factor of 2 towards the bottom. The main implications of discovered freeze-driven solute concentrations in thermokarst lake waters are enhanced colloidal coagulation and removal of dissolved organic matter and associated insoluble metals from the water column to the sediments. The measured distribution coefficients of a TE between amorphous organo-ferric coagulates and lake water (<0.45 μm) were similar to those reported earlier for Fe-rich colloids and low molecular weight (<1 kDa, or <1–2 nm) fractions of thermokarst lake waters, suggesting massive coprecipitation of TE with amorphous Fe oxyhydroxide stabilized by organic matter. Although the concentration of most elements was lowest in spring, this period of maximal water coverage of land created a significant reservoir of DOC and soluble metals in the water column that can be easily mobilized to the hydrological network. The highest DOC concentration observed in the smallest (<100m2) water bodies in spring suggests their strongly heterotrophic status and, therefore, a potentially elevated CO2 flux from the lake surface to the atmosphere

Permafrost coverage, watershed area and season control of dissolved carbon and major elements in western Siberian rivers

Analysis of organic and inorganic carbon (DOC and DIC, respectively), pH, Na, K, Ca, Mg, Cl, SO₄ and Si in ~ 100 large and small rivers (< 10 to &le; 150 000 km²) of western Siberia sampled in winter, spring, and summer over a more than 1500 km latitudinal gradient allowed establishing main environmental factors controlling the transport of river dissolved components in this environmentally important region, comprising continuous, discontinuous, sporadic and permafrost-free zones. There was a significant latitudinal trend consisting in a general decrease in DOC, DIC, SO₄, and major cation (Ca, Mg, Na, K) concentration northward, reflecting the interplay between groundwater feeding (detectable mostly in the permafrost-free zone, south of 60° N) and surface flux (in the permafrost-bearing zone). The northward decrease in concentration of inorganic components was strongly pronounced both in winter and spring, whereas for DOC, the trend of concentration decrease with latitude was absent in winter, and less pronounced in spring flood than in summer baseflow. The most significant decrease in K concentration from the southern (< 59° N) to the northern (61–67° N) watersheds occurs in spring, during intense plant litter leaching. The latitudinal trends persisted for all river watershed size, from < 100 to > 10 000 km². Environmental factors are ranked by their increasing effect on DOC, DIC, δ¹³C_DIC, and major elements in western Siberian rivers as follows: watershed area < season < latitude. Because the degree of the groundwater feeding is different between large and small rivers, we hypothesize that, in addition to groundwater feeding of the river, there was a significant role of surface and shallow subsurface flow linked to plant litter degradation and peat leaching. We suggest that plant-litter- and topsoil-derived DOC adsorbs on clay mineral horizons in the southern, permafrost-free and discontinuous/sporadic permafrost zone but lacks the interaction with minerals in the continuous permafrost zone. It can be anticipated that, under climate warming in western Siberia, the maximal change will occur in small (< 1000 km² watershed) rivers DOC, DIC and ionic composition and this change will be mostly pronounced in summer

Resources, regime and quality of surface waters in the Ob River basin: history, current state and problems of research

The paper presents the history and major results of research into resources, regime and quality of the surface water in the Ob basin, concentrated in such water bodies as glaciers, rivers, lakes, reservoirs and wetlands. Studies have long been carried out by such government agencies as the Hydrometeorological Service (Hydromet), the Ministry of Energy and others, engineering organizations, scientific research institutes of the academy of sciences and universities. The studies included large complex tasks aimed at economic development of the basin territory. By the 1980s, an expanded network of stationary hydrological observations existed, and basic information about the factors of resources formation, regime and surface water quality, as well as long-term dynamics of hydrological characteristics had been obtained. Today, a multidisciplinary and interdisciplinary approach to the hydrological cycle and geo-run-off at the global and regional scales is related to the changes in climate and the environment in general

Resources, regime and quality of surface waters in the Ob River basin: history, current state and problems of research

The paper presents the history and major results of research into resources, regime and quality of the surface water in the Ob basin, concentrated in such water bodies as glaciers, rivers, lakes, reservoirs and wetlands. Studies have long been carried out by such government agencies as the Hydrometeorological Service (Hydromet), the Ministry of Energy and others, engineering organizations, scientific research institutes of the academy of sciences and universities. The studies included large complex tasks aimed at economic development of the basin territory. By the 1980s, an expanded network of stationary hydrological observations existed, and basic information about the factors of resources formation, regime and surface water quality, as well as long-term dynamics of hydrological characteristics had been obtained. Today, a multidisciplinary and interdisciplinary approach to the hydrological cycle and geo-run-off at the global and regional scales is related to the changes in climate and the environment in general

Estimation of water balance over catchment areas taking into account the heterogeneity of their landscape conditions

The landscape conditions for forming the water balance and runoff from catchment areas can change considerably under the pressure of natural and anthropogenic factors. The role of hydromorphic transformation of landscapes is important for most of the Ob basin; it results in the paludification of the area. The specific parameter n is used in calculating water balance according to Mezentsev’s method of hydro-climatic calculations to take account of landscape conditions. We suggest determining this parameter’s value by geomorphological features of the landscapes using GIS tools

Estimation of water balance over catchment areas taking into account the heterogeneity of their landscape conditions

The landscape conditions for forming the water balance and runoff from catchment areas can change considerably under the pressure of natural and anthropogenic factors. The role of hydromorphic transformation of landscapes is important for most of the Ob basin; it results in the paludification of the area. The specific parameter n is used in calculating water balance according to Mezentsev’s method of hydro-climatic calculations to take account of landscape conditions. We suggest determining this parameter’s value by geomorphological features of the landscapes using GIS tools

Climate of West Siberia during the slowing phase of warming (1986–2015) and prediction of hydro-climatic resources for 2021–2030

The relevance of the study. The most visible affect of the present climate change is the rise of surface air temperature. Regional and local indicators of climate change differ from the global characteristics. Transformation of the hydrological cycle, water balance, river runoff in its turn affects climate processes. In order to predict the response of geosystems and their hydro-climatic resources to climate change it is necessary to have a clear vision of contemporary climate change and its projections for the coming decades in specific geographical localities. The aim of the study is (1) to assess the climate change over West Siberia on the basis of statistical analysis of monthly air temperature and precipitation time series up to 2015, (2) predict the average air temperature and precipitation fields for the 2021-2030, and (3) determine the climate-driven changes in water balance and water flow regime over the study area. The methods used in the study. Analysis and forecasting of spatial and temporal variability of surface air temperature and precipitation rates at meteorological stations in the region are made by statistical methods in the StatSoft STATISTICA package (regression analysis, trend analysis, cluster analysis to classify objects, exponential smoothing and forecasting). The averaged monthly land water balance constituents are determined for the base (1966-1985), current (1986-2015) and forecast (2021-2030) using the method of hydrological and climatical calculations developed by V.S. Mezentsev. The results. It is shown that the modern 30yrs climatic period differs from the previous one in higher energy level (air temperature). Against this background, not only upward but downward temperature trends in some months are observed. The authors have predicted the average temperatures and precipitation rates in a cold season and monthly temperatures and precipitation in a warm season of the year at 31 meteorological stations for 2021-2030. The estimates for the current and forecast periods made it possible to compute the average regime parametres of precipitation, evapotranspiration, runoff and moisture of soil active layer at the meteorological stations located in different lanscape zones and regions of West Siberian plain. The projected increase in temperature and evapotranspiration does not lead to the expected decrease in flow even in the southern dry regions. At the same time, soil moisture in summer will decrease everywher