Laboratory investigation of damping of gravity-capillary waves on the surface of turbulized liquid

Investigation of damping of gravity-capillary waves (GCWs) in the presence of turbulence is a classical hydrodynamic problem which has important geophysical applications, one of which is related with the problem of forming a radar and optical image of a ship wake on wavy water surface. In this work a new method for the laboratory study of surface wave damping in turbulized liquid is described and the results are presented. The damping of standing GCWs by turbulence on the water surface in a tank mounted on a vibration table is studied. GCWs and turbulence are excited using a two-frequency mode of vibration table oscillations. A high-frequency small amplitude signal is used for parametric GCW excitation; a low-frequency large amplitude signal is used for generating turbulence due to water flowing through a fixed perforated grid submerged into the tank. The coefficient of GCW damping is determined by measured threshold of parametric excitation of the waves; turbulence characteristics are determined by the PIV and PTV techniques. Dependences of GCW damping coefficients on their frequency at different turbulence intensities are obtained, estimates for turbulent viscosity are presented, and a comparison with empirical models proposed earlier is performed.     

The use of the Ground Penetrating Radar (GPR) method in engineering-geological studies for the assessment of geological-cryological conditions

We present the results of the use of the Ground Penetrating Radar (GPR) method on saline and nonsaline soils in permafrost rock zones. GPR records are geologically interpreted during thermokarst and pingo study. The usefulness of the GPR method for mapping the top and bottom of permafrost rocks is explored for saline soils.     

Biogeochemistry of calcium and strontium in the landscapes of eastern Transbaikalia

This paper reports data on the contents and ratios of Ca and Sr in the soils, waters, and plants of eastern Transbaikalia and the Baikal region. The contents of Ca in the soils, waters, and plants of endemic areas affected by Urov disease approach those in objects from control areas. The contents of Sr in the soil–plant complex of the Urov biogeochemical province are relatively high and show spotted distribution, which is related to the landscape-geochemical characteristics of the region. It was found that the Ca/Sr values in the soils of a number of areas unaffected by Urov disease of animals and humans fall mainly within 11–236 (53 ± 24 on average). In the soils of endemic regions in eastern Transbaikalia, Ca/Sr ranges from 2 to 98 (36 ± 11 on average). The hay crop of meadow plants show Sr contents of 72.8 ± 31.6 mg/kg (endemic region) and 36.6 ± 15.7 mg/kg (control areas) and Ca/Sr values of 250 ± 115 and 525 ± 382, respectively. The elevated Sr content in the soils and plants of the endemic region is considered as a factor of ecological risk.     

Ecological–Biogeochemical Monitoring of a Linden Avenue in a Megapolis

Ecological–biogeochemical monitoring of a linden avenue on Kosygin Street, Moscow, has revealed that soils at sites regarded as contaminated contain elevated Mn, Fe, Sr, and Se concentrations and lower Zn contents. Linden leaves at the assumed contaminated sites typically contain higher Cu and Fe concentrations and not as much higher Zn, As, and Cr concentrations but much lower Mn and Sr concentrations. Water leachates of soils at sites regarded as background have slightly lower pH and lower Ca, Mg, K, and Na concentrations and total mineralization. Test for phytochelatins in the leaves proved to be rather ineffective, as also were estimates of the fluctuating asymmetry of the leaf laminas. The greatest differences were detected in the degree of leaf pathology and the contents of pigments.     

A modern analogue of the Pleistocene steppe‐tundra ecosystem in southern Siberia

Steppe‐tundra is considered to have been a dominant ecosystem across northern Eurasia during the Last Glacial Maximum. As the fossil record is insufficient for understanding the ecology of this vanished ecosystem, modern analogues have been sought, especially in Beringia. However, Beringian ecosystems are probably not the best analogues for more southern variants of the full‐glacial steppe‐tundra because they lack many plant and animal species of temperate steppes found in the full‐glacial fossil record from various areas of Europe and Siberia. We present new data on flora, land snails and mammals and characterize the ecology of a close modern analogue of the full‐glacial steppe‐tundra ecosystem in the southeastern Russian Altai Mountains, southern Siberia. The Altaian steppe‐tundra is a landscape mosaic of different habitat types including steppe, mesic and wet grasslands, shrubby tundra, riparian scrub, and patches of open woodland at moister sites. Habitat distribution, species diversity, primary productivity and nutrient content in plant biomass reflect precipitation patterns across a broader area and the topography‐dependent distribution of soil moisture across smaller landscape sections. Plant and snail species considered as glacial relicts occur in most habitats of the Altaian steppe‐tundra, but snails avoid the driest types of steppe. A diverse community of mammals, including many species typical of the full‐glacial ecosystems, also occurs there. Insights from the Altaian steppe‐tundra suggest that the full‐glacial steppe‐tundra was a heterogeneous mosaic of different habitats depending on landscape‐scale moisture gradients. Primary productivity of this habitat mosaic combined with shallow snow cover that facilitated winter grazing was sufficient to sustain rich communities of large herbivores.     

A Spectral Atlas of F and G Stars

We present an atlas of a group of bright stars in the range of spectral classes F-G and luminosity classes I-V. The spectra were obtained with spectral resolution R ～ 15 000 within spectral region 4500-6620/A Typical spectra of stars with different metallicity [Fe/H] are included. We also show the digital version of the spectral data in FITS format.     

High Resolution Spectroscopy of Halo Stars in the Near UV and Blue Region I. Spectra in the Wavelength Region 3550-5000 A

An atlas of high resolution (R = 60 000) CCD-spectra in the wavelength range 3500-5000A is presented for four objects in metallicity range -3.0 < [Fe/H] < -0.6, temperature range 4750 < Teff < 5900 K, and surface gravity range 1.6 < lgg < 5.0. We describe the calibration of the stellar atmospheric parameters using Alonso's formula based on the method of infrared flux and outline the determination of the abundances of a total number of 25 chemical elements. An analysis of the abundance determination errors for different chemical elements is carried out, and a method is provided for the observations and reduction of spectral material. Properties of the method of producing an atlas of spectra and line identifications are described.     

A.P. Vinogradov’s concept of biogeochemical provinces and its development

This paper addresses the concept of biogeochemical provinces introduced by A.P. Vinogradov and developed by V.V. Kovalsky and other researchers. The importance of this scientific direction was emphasized in the context of the anthropogenic impact on the biosphere. The most general characteristics, genesis, and evolution of biogeochemical provinces were discussed. Special attention was given to modern natural–anthropogenic biogeochemical provinces and anomalies. It was pointed out that this modern and vitally important scientific direction should be further pursued.     

Global Circulation of Latent Heat in the Earth’s Atmosphere According to Data from Satellite Radiothermovision

Izvestiya, Atmospheric and Oceanic Physics - The methodical bases and some results of using satellite radiothermovision to study global atmospheric latent heat circulation according to the data of...