Registration of weak ULF/ELF oscillations of the surface electric field strength

Measurements of the atmospheric electric field strength made by an electrostatic fluxmeter with a unique threshold sensitivity for such devices (6 × 10^–2–10^–3 V m^–1 Hz^–1/2 in the 10^–3–25 Hz frequency range) and wide dynamic (120 dB) and spectral (0–25 Hz) ranges, are presented. The device parameters make it possible to observe the electric component of global electromagnetic Schumann resonances and long-period fluctuations in the atmospheric electric field strength.     

Piezoremanent magnetization of the ensemble of single-domain particles

Using the model of single-domain particles, a theoretical analysis of the properties of different forms of piezoremanent magnetization is carried out. The relationships which determine piezoremanent magnetization within the entire range of stresses are obtained. Two mechanisms of magnetization are revealed. It is shown that in the weak field approximation the magnetization of the first type has a quadratic dependence on the magnetic field and weakly depends on stresses, while another type of magnetization, which mainly determines the piezomagnetic effect, is proportional to the field and stresses. Moreover the magnetization that forms in the course of a change in stresses parallel to the field is always higher than the magnetization that appears as a result of action perpendicular to the field.     

Variations of contemporary glaciation of the northern slope of the Greater Caucasus in the 20th century and the forecast of its degradation in the 21st century

In the 20th century on the territory of the northern slope of the Greater Caucasus the number of glaciers increased by 245 (or by 19%) and the glaciation area decreased by 849 km² (or by 52.6%). It is revealed that the increase in the number of glaciers occurred as a result of the disintegration of larger glaciers into smaller parts and as a result of the cutoff of their tributaries, and the decrease in the glaciation area, due to the negative balance of the mass of glaciers. The length of all glaciers decreased by 128–3520 m during that period. It is demonstrated that in 1970–2011 the decrease in the glaciation area occurred with the rate being smaller than in 1895–1970 by 1.6 times that is associated with more favorable climatic conditions in 1970–2011. According to the computations of the climate model by the Main Geophysical Observatory (moderate scenario) for 2011–2099, average annual air temperature will increase by 1.06–2.70°C and the annual amount of precipitation, by 2.09–2.77%. According to the results of computations, the glaciation area in 2011–2099 will reduce by 585 km² or by 76.5%. In the region under consideration, glaciation with the area of 180 km² which will be concentrated only in the central part of the Greater Caucasus will maintain by 2099. The glacier runoff will decrease by 74–80%.     

The K–Ar and Rb–Sr Isotopic Systems in Rocks from the Jurassic Terrigenous Complex of the Greater Caucasus

The behavior of K–Ar and Rb–Sr isotopic systems in clayey rocks from the Jurassic terrigenouis complex of the Greater Caucasus sampled along the Terek River is discussed. It is shown that the rocks experienced intense postdiagenetic alterations accompanied by substantial changes in mineral composition and K–Ar and Rb–Sr isotopic systems. Lateral stress is the leading factor responsible for secondary mineral and geochemical transformations of rocks in cleavage zones. Rejuvenation of the radiological age of rocks, relative to their stratigraphic age, is 100 Ma and more. The age estimate of approximately 50 Ma obtained for samples from the southern limb of the anticlinorium reflects the Paleocene–Eocene phase of tectonic activity manifested in both the Caucasus and other areas of the Mediterranean foldbelt.     

Post-glacial diatom and geochemical records of ecological status and water level changes of Lake Vorota,Western Beringia

Journal of Paleolimnology - In this study, radiocarbon-dated geochemical and diatom records from Lake Vorota located within the informal meteorological ‘pole of cold’ of the northern...     

Specific features of the interannual and seasonal variations of hydrometeorological conditions in the region of Kerch Strait for the last two decades

On the basis of the analysis of the archival data, we reveal some regularities of the interannual and seasonal variations of the parameters of atmospheric transport, winds, air temperature, the amount of atmospheric precipitation in the Kerch region, the temperature of water in the Kerch Strait, and the water discharge through the strait observed for about the last two decades. It is shown that the intensities of the southeast atmospheric transport and wind activity predominant for the previous 30-yr period decreased for the analyzed time period as compared with the previous period, whereas the amount of atmospheric precipitation and the annual average temperatures of water in the strait and air in the Kerch region increased. We also reveal the presence of direct qualitative relationship between the intensity of atmospheric transport over the Kerch Strait and the water discharge in its water area.     

Photometric and spectroscopic observations of the variable star ET And. II

New spectroscopic and photometric observations of the variable Ap star ET And carried out 1982 and 1983 confirm once again the existence of short-time variations. For the radial velocity variations a period of 0.19771 days and for the light variations a period of 0.0989 days was found. Some spectrograms show a velocity progression of the Balmer lines. The gradient is of such a kind that the radial velocity values increase from the line H_γ to H₁₅. Different models for the interpreation of the velocity progression are discussed.