Aromatic volatile organic compounds and their role in ground-level ozone formation in Russia

This paper reports proton mass spectrometry data on aromatic volatile organic compounds (VOCs) (benzene, toluene, phenol, styrene, xylene, and propylbenzene) obtained in different Russian regions along the Trans-Siberian Railway from Moscow to Vladivostok, based on expedition data retrieved using the TRO-ICA-12 mobile laboratory in the summer of 2008. The contribution of aromatic VOCs to ozone formation in the cities and regions along the measurement route has been estimated quantitatively. The greatest contribution of aromatic VOCs to ozone formation is characteristic of large cities along the Trans-Siberian Railway (up to 7.5 ppbv O₃) specified by the highest concentrations of aromatic VOCs (1–1.7 ppbv) and nitrogen oxides (>20 ppbv). The results obtained are indicative of a considerable contribution (30–50%) of anthropogenic emissions of VOCs to photochemical ozone generation in the large cities along the Trans-Siberian Railway in hot and dry weather against the background of a powerful natural factor such as isoprene emissions controlling the regional balance of ground-level ozone in warm seasons.

     

Pleiades luminosity function: fine structure and new Pre‐MS models

In order to study a model‐dependence of the results achieved in the previous investigations of the Pleiades luminosity function using D'Antona and Mazzitelli (1994) evolutionary tracks, we repeated the computations with the new track system by D'Antona and Mazzitelli (1997). The following main conclusions can be drawn: the new models agree better with observations; the helium abundance needed to fit the Hipparcos distance modulus is reduced to a more reasonable value of Y = 0.31; the cluster age becomes slightly higher and the slope of the initial mass function somewhat lower. The conclusions on the fine structure of the luminosity function do not change significantly due to the application of the new models.     

Ozone and nitric oxides in the surface air over northern Eurasia according to observational data obtained in TROICA experiments

The results of the 1995–2008 observations of the concentrations of ozone and nitric oxides in the surface air over the Trans-Siberian Railway using a mobile laboratory (the TROICA experiments) are analyzed. The features of the spatial distribution and time variability of these gases over the continent within the latitudinal belt 48°–58° N are revealed individually for polluted and background conditions. The characteristic features of their distribution are a decrease in the concentration of nitric oxides and an increase in the concentration of ozone in an eastward direction. On the whole, the process of photochemical ozone formation over the territory of Siberia is slow. Noticeable increases in the concentration of ozone are associated with both forest and steppe fires and with the transboundary transport of pollution from the countries of eastern Asia. The dry precipitation of trace gases plays a significantly larger role in Siberia than in coastal and high-altitude unpolluted regions due to powerful and long temperature inversions.     

Gaseous admixtures in the atmosphere over Moscow during the 2010 summer

In the summer of 2010, the Moscow megacity during two months was within the zone of action of a blocking anticyclone. The accumulation of pollutants in a closed air mass sharply changed the surface air quality. At the end of July-the first half of August, the extreme situation became even more complicated, because the air from regions of turf and grass fires came into Moscow. According to measurement data of the Moscow IAP RAS station, the maximal hourly mean concentrations of chemically active gases NO, NO₂, CO, O₃, and SO₂ were 175.9, 217.4, 15.8, 134.2, and 15.2 ppb, respectively. For NO₂ and CO, these values are largest over the entire decadal period of observations at the station and many times exceed the MPC level (see table). The concentrations of greenhouse gases CO₂, CH₄, and nonmethane hydrocarbons also sharply increased. Analysis of the variability of gas contents in the surface air and in the atmospheric boundary layer showed a close relation between extreme changes in the atmospheric composition and its vertical stratification.     

Scaling Astro-WISE to LOFAR long term archive

The Astro-WISE information system was developed to handle data processing for the KIDS survey. In this paper we describe the adaptation of the WISE concept to allow scaling to support archives containing tens of petabytes of stored data and the changes we introduced to accommodate the system for the LOFAR Long Term Archive. With this we provide an example of how Astro-WISE technology can be adapted to support a wider range and scale of data.     

Mathematical Modeling of Spring Flood Passing through the Urban Reach of the Moskva River

A mathematical model is proposed to describe the urban reach of the Moskva River. The model allows estimating the stream characteristics for the period of spring flood passage, hydraulic washing of the channel with allowance for different regimes of water flow at overflow dams. It is shown that this model can be used to construct the curves of throughput capacity of overflow dams as well as the levels of water surface and the boundaries of inundation zones and the flow rates and velocities within the city.     

Retrospective Simulation of an Extreme Flood on the Oka River at the City of Ryazan and Impact Assessment of Urban and Transport Infrastructure

Numerical modeling of flow dynamics of rivers with comprehensive channel patterns and wide floodplains during high water stage is considered to be one of the most effective methods for implementing both research and civil-engineering projects. However, realistic results of simulations can be obtained only if the model has been calibrated and validated against field observations and remote sensing data. This approach is realized for a 2D hydrodynamic model of the Oka River at the city of Ryazan (central European Russia). The Oka has a meandering channel and a wide floodplain with a complicated distributary network. The feasibility of allocating new residential quarters and infrastructure facilities on artificial “islands” on the floodplain was studied using STREAM_2D software package. Because of a significant decrease in the maximum runoff of the Oka in the recent decades, the simulations were made for the extreme spring snowmelt flood of 1970 for various scenarios of floodplain development in the past, present, and future.

     

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.     

Analysis of the Impact of Hydrotechnical Construction on the Amur River near Blagoveshchensk and Heihe Cities Using a Two-Dimensional Hydrodynamic Model

Water flow and sediment transport under the effect of hydrotechnical constructions on the Amur River near Blagoveshchensk and Heihe cities was analyzed based on two-dimensional hydrodynamic modeling using STREAM_2D software (the authors V. Belikov et al., Russia). Three modeling scenarios were considered: without constructions, with the embankment of Blagoveshchensk, with the embankment of Blagoveshchensk and a system of dams near the Chinese island of Big Heihe. Modeling results have shown that the embankment has only a local effect on the part of the Amur R. upstream from confluence with the Zeya R. The construction of dams in the side channels near the island of Big Heihe can lead to significant flow redistribution, providing the flow concentration in the main river channel and reduction of the water flow, entering the island system. An increase in erosion in the main channel downstream of the confluence near the left bank and a simultaneous increase in accumulation near the right bank of the Amur R. below the island system can take place as the result of side channels shutting by dams from the right bank.