卷 44, 编号 5 (2017)

Regularities in the secular variations of water level in the Great Lakes of Eurasia and North America under natural climate and anthropogenic impacts are studied.

The main freshwater source of arid/semi-arid Central Asia is stored in its high mountain glaciers. Water for the downstream countries is mainly supplied through the Syrdarya River that originates at the confluence of the Naryn and Karadarya rivers in the Ferghana Valley. Runoff generation from glaciers plays a crucial role, although a considerable number of small tributaries supply the river with additional runoff from snowmelt and rain in the mountains surrounding the Ferghana Valley. Observations of rising air temperature and accelerated glacier shrinkage make it most likely that the relative contributions of the smaller tributaries will increase. Hitherto, assessments of climate change effects on the water resource availability have largely neglected the growing importance of the runoff from smaller tributaries. We used a dynamically downscaled A1B SRES scenario for climate change effects for the period 2071–2100 in relation to the reference period of 1971–2000 and a version of the conceptual hydrological Hydrologiska Byråns Vattenavdelning model (HBV-light) to estimate runoff contributions with particular respect to the small tributaries. The simulations showed a 12–42% decrease in summer runoff; and a 44–107% increase in winter-spring runoff. This indicates the hydrological regime is shifting towards a runoff from snowmelt earlier in the year. The study suggests that actions for climate change adaptation should be complemented by land management configured to secure optimal runoff supplement from the smaller catchments.

A mathematical model has been developed to assess the role of the shape of channel cross-section, the position of pollutant source on the bank slope, and the sedimentation rate of pollutant particles in the process of pollutant transport in water flow. The procedure of numerical experiments and the obtained results and conclusions can be of use in the simulations and studies of pollution propagation from sources on riverbanks in permafrost zone, which are subject to thermal erosion.

A brief review of studies of the hydrological regime of the Sea of Azov and approaches to assessing the average salinity—a key indicator of the state of its ecosystem is given. A database of salinity measurements at 47409 oceanographic stations over hundred years (from 1913 to 2014) were used to evaluate the sea-averaged mean annual salinity. The obtained values of the average salinity were found to differ from those published before because of the different approaches used to its calculation and different volumes of data involved. The difference was most significant for Taganrog Bay because of the high variability of its hydrological regime. Anomalies of the average salinity over period 1922–2014 were constructed, and the start of one more period of salinity increase in the Sea of Azov was recognized.

Digital databases on 444 stations were used to carry out statistical analysis of regularities in the spatial distribution of Barents Sea water pollution. The analysis was focused on the concentrations in water of heavy metals (Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and toxic organic compounds: hexachlorocyclohexanes, hexachlorobenzene, chlordans, DDT, polychlorbiphenyls, polycyclic aromatic hydrocarbons, and normal paraffins. The statistical analysis of data on pollutants was carried out along two major directions in their distribution: the vertical—in the surface and bottom water layers; and the horizontal—over water masses. Reliable differences were identified in the pollution level of different water masses of the Barents Sea. The frontal zone was found to concentrate pollution.