Ladoga and Onega Hydrological Regimes and Their Variations

The characteristics of the Ladoga and Onega hydrological regimes were analyzed, and the features of the annual and long-term variations in their water balance components were determined. The statistically significant positive trends of the average annual precipitation and evaporation in the Ladoga water area and the water inflow for the period of 1932–1995 were determined. The relative effect of the Ladoga water balance components on the formation of its level was studied. Spectral analysis of the components of this balance revealed, in particular, characteristic periods of about four years in the last decades. Based on the analysis, including wavelet, of the longer series of long-term variations in the Ladoga water level, it was found that the spectral structure pronouncedly changed in the period from 1859 to 1995.     

Justification of Hydrological Safety Conditions in Residential Areas Using Numerical Modelling

The present paper looks at the application of modern technology of numerical modelling to simulate natural and human-induced river floods of residential areas. The modelling is based on the use of 2D shallow-water equations and 3D digital terrain models. The application of adaptive mesh generator and effective algorithms of parallel computing using NVIDIA graphics processors with CUDA technology enables calculating the areas and depths of flooding in a big city, taking into account all residential, industrial, and road constructions. Each one of them is specifically singled out on the mesh. This enables the reproduction of the real course of a flood well.     

Developing methods for bioidentification of xenobiotics for water quality assessment

The role of bioassay in the pollution control system for water bodies is considered. Studies of the mechanisms of toxic impact of various chemical compounds on aquatic organisms were used to develop a bioindication method to give an integral estimate of water toxicity and determine some classes of chemical pollutants. The results of application of such methods to assessing water quality in Lake Ladoga are given.     

Variations of temperature and hydrologic regimes of the region of Ladoga Lake catchment basin in the 20th and 21st centuries according to data of modern climate models

In the region of the Ladoga Lake catchment basin, we perform data analysis on a set of different modern climate models with different Intergovernmental Panel on Climate Change (IPCC) scenarios in the 20th and 21st centuries; this set includes global models such as ECHAM4/OPYC3 (Max Planck Institute for Meteorology, Germany), HadCM3 (Hadley Centre Coupled Model, England), and RCAO (Rossby Centre Regional Atmosphere-Ocean) models. Two variants of the boundary conditions for these climate models (Rossby Center of Swedish Meteorological and Hydrological Institute, SMHI) are used. We present the results of a diagnosis of the model-predicted near-surface temperature (T), precipitation (P), evaporation (E), and water budget (P-E) in the Ladoga Lake catchment based on their comparison with empirical data in twentieth century. We obtain scenario estimates of the variations of temperature and hydrologic regimes of Ladoga Lake catchment when IPCC IS92a, A2, and B2 scenarios are fulfilled, describing the prognostic growth of anthropogenic emissions of greenhouse gases and aerosol to the atmosphere, and discuss the recommendations for their use.     

Determining the Velocity of the Upper Layer of Lake Ladoga by Means of Maximum Cross Correlation (MCC)

Izvestiya, Atmospheric and Oceanic Physics - The first use of Maximum Cross Correlation to calculate the surface currents of Lake Ladoga yields very promising results in the absence of direct...     

Assessing the Hazard Due to the Effect of Heat Discharges from the Novocherkasskaya SDPP on the Hydroecological Regime of the Lower Don Taking into Account the Future Bagaevskoe Reservoir

Water Resources - The article presents the results of numerical hydrothermal simulation of changes in the temperature regimes of the Don River under the effect of heat discharges of the...     

Host galaxy of the dark gamma-ray burst GRB 051008

We have discovered and studied the host galaxy of the “dark” gamma-ray burst GRB051008, a burst for which no optical afterglow has been detected. We studied the properties and determined the redshift of the host galaxy and analyzed its neighborhood. We perform a comparative analysis of the properties of GRB051008 and its host galaxy with the properties of other known dark gamma-ray bursts. We analyze the causes of the lack of optical afterglow in this gamma-ray burst.     

The cosmic rays of superhigh energies

The paper considers the generation mechanism of the relativistic particles of superhigh energies (10¹⁸ eV) in a plasma where the supersonic turbulence and the hydrodynamic shock waves occur. It is found that the conditions necessary for the formation of this turbulence are realized in supernovae shells during the period of the outburst. The estimations of the energy gain rate of the charged particles and comparison with their energy loss rate conditioned by synchrotron radiation and collisions with photons and nuclei show that in the actually determined conditions of shells in Crab and Cassiopeia nebulae, at the early stages of their expansion, acceleration surpasses deceleration. And finally, the estimations of the total number of superhigh energy particles generated during the flare are in agreement with the observed data.