The physical basis of the effects caused by electromagnetic forcing in the intensity of geoacoustic processes     

V. A. Gavrilov  I. A. Panteleev  G. V. Ryabinin 《Izvestiya Physics of the Solid Earth》2014,50(1):87-101

The results of theoretical and experimental investigations into the physical causes and mechanisms of the electromagnetic effects that modulate the intensity of the geoacoustic processes are presented. The peculiarities of this effect before strong nearby earthquakes are studied.  相似文献   

Statistical inhomogeneity of dates of sudden stratospheric warmings in the wintertime northern hemisphere     

E. N. Savenkova  N. M. Gavrilov  A. I. Pogoreltsev  R. O. Manuilova 《Izvestiya Atmospheric and Oceanic Physics》2017,53(3):251-258

Using the data of meteorological information reanalysis, a statistical analysis of dates of the main sudden stratospheric warmings observed in 1958–2014 has been performed and their inhomogeneous distribution in winter months with maximums in the beginning of January, from the end of January to the beginning of February, and in the end of February has been shown. To explain these regularities, a climatological analysis of variations in the amplitudes and vertical components of Eliassen–Palm fluxes created by large-scale planetary waves (PWs), as well as of zonal-mean winds and deviations of temperature from their winter-average values in high northern latitudes at heights of up to 50 km from the surface has been carried out using the 20-year (1995–2014) collection of daily meteorological information from the UK Met Office database. During the aforementioned intervals of observing more frequent sudden stratospheric warmings, climatological maximums of temperature perturbations, local minimums of eastward winds, and local maximums of the amplitude and Eliassen–Palm fluxes of PWs with a zonal wavenumber of 1 in the high-latitude northern stratosphere were found. Distinctions between atmospheric characteristics averaged over two last decades have been revealed.  相似文献   

Events at the turn of the Eocene and Oligocene in the Central Eurasia Region (middle latitudes)     

M. A. Akhmetiev  Yu. O. Gavrilov  N. I. Zaporozhets 《Doklady Earth Sciences》2017,473(1):273-276

The Eocene and Oligocene transition sections (Priabonian–Rupelian) of the Aral–Turgai, West Siberian, Volga–Don, and Crimea–Caucasus regions have been studied in detail [1], and the global biospheric crisis events have been estimated at the turn of the Eocene and Oligocene. In spite of the idea of the gradual regression in the Priabonian with drainage of the inner sea basins, it has been established that shallowing of the sea was preceded by repeated transgression that continued for 1 Ma with warming up and humidification of the climate. The final regressive phase (130–200 ka) was accompanied by frequent eustatic and climatic fluctuations, reconstruction of the isotopic and geochemical background, and also the recurrence at the boundary between layers in certain continuous sections.  相似文献   

Mesozoic and Early Cenozoic Paleoecological Events in the Sedimentary Record of the NE Peri-Tethys and Adjacent Areas: An Overview     

Gavrilov  Yu. O.  Shcherbinina  E. A.  Aleksandrova  G. N. 《Lithology and Mineral Resources》2019,54(6):524-543

Lithology and Mineral Resources - Manifestations of short-term global and subglobal events have been recognized in the Mesozoic and Cenozoic sedimentary record of the North Caucasus:...  相似文献   

Field-aligned current generation at plasma clouds or bodies with plasma shells moving in magnetic fields     

B. G. Gavrilov  I. M. Podgorny  J. I. Zetzer 《Earth, Moon, and Planets》1996,72(1-3):481-486

Field-aligned currents (FAC) can be generated during a plasma jet or the motion of a body with a plasma shell in a transverse magnetic field. They can be investigated in an active space experiment. For the proper choice of diagnostics and for evaluation of expected results a laboratory simulation is carried out. The preliminary results show FAC generation in conditions correlated with conditions in space.  相似文献   

Parametrization of momentum and energy depositions from gravity waves generated by tropospheric hydrodynamic sources     

N. M. Gavrilov 《Annales Geophysicae》1997,15(12):1570-1580

The mechanism of generation of internal gravity waves (IGW) by mesoscale turbulence in the troposphere is considered. The equations that describe the generation of waves by hydrodynamic sources of momentum, heat and mass are derived. Calculations of amplitudes, wave energy fluxes, turbulent viscosities, and accelerations of the mean flow caused by IGWs generated in the troposphere are made. A comparison of different mechanisms of turbulence production in the atmosphere by IGWs shows that the nonlinear destruction of a primary IGW into a spectrum of secondary waves may provide additional dissipation of nonsatu-rated stable waves. The mean wind increases both the effectiveness of generation and dissipation of IGWs propagating in the direction of the wind. Competition of both effects may lead to the dominance of IGWs propagating upstream at long distances from tropospheric wave sources, and to the formation of eastward wave accelerations in summer and westward accelerations in winter near the mesopause.  相似文献   

On the dynamic mechanism of formation of rift valleys     

S. V. Gavrilov  A. N. Boiko 《Izvestiya Physics of the Solid Earth》2006,42(4):282-285

A dynamic mechanism that accounts for the sinking of a lithospheric plate near an accretion zone in the vicinity of a passive rift is revealed. It is shown that the influence of the underlying “cold” mantle can be described in terms of a concentrated vertical force applied to the rift axis. At a moderate spreading rate, the value of this force is an order of magnitude smaller than the characteristic values of forces acting in the plate tectonics. The average viscosity coefficient of the cold upper mantle is estimated at ～10²¹ P. The concentrated force at the rift axis produces a characteristic topography of the rift valley type of mid-ocean ridges.  相似文献   

Factors triggering landslide occurrence on the Zemun loess plateau,Belgrade area,Serbia     

Tin Lukić  Dajana Bjelajac  Kathryn E. Fitzsimmons  Slobodan B. Marković  Biljana Basarin  Dragan Mlađan  Tanja Micić  Randall J. Schaetzl  Milivoj B. Gavrilov  Miško Milanović  György Sipos  Gábor Mezősi  Nevenka Knežević-Lukić  Miroljub Milinčić  Aleš Létal  Ivan Samardžić 《Environmental Earth Sciences》2018,77(13):519

Among the numerous factors that trigger landslide events, the anthropogenic impact caused by inadequate planning and faulty land use in urban areas is increasing. The Zemun settlement on the northern outskirts of Belgrade has experienced a number of landslides in the last three decades, endangering buildings and roads, and claiming human lives, particularly in the case of the 2010/2011 landslides. Selected meteorological parameters were used to calculate rainfall erosivity indices such as Precipitation Concentration Index and Modified Fournier Index over the period 1991–2015. Drought indices, Lang aridity index and Palfai Drought Index were calculated as well. Mann–Kendall trend test was applied to identify potential rising and/or declining trends both in meteorological parameters and calculated indices. Trend analysis of the annual and seasonal scales yielded a statistically significant trend in the spring time series. Stable arid and pronounced drought conditions were recorded. The modified Fournier index based on monthly mean values yields moderate aggressiveness, with several extreme values indicating very high erosivity classes, especially for 2010/2011. The geological substrate is predominantly loess and hence highly susceptible to erosion and slope failure when climatological conditions are suitable. Accelerated urbanization at the end of the last century reduced vegetation cover, intensified pressure on the vertical loess slope, and lacked suitable rain drainage systems so that surface-water runoff was directed into the porous loess, thereby endangering slope stability. We proposed a geomorphic model to describe the nature of the erosional processes on the loess cliffs of the Zemun loess plateau. Results from this study have implications for mitigation strategies.  相似文献   

Malaco temperature reconstructions and numerical simulation of environmental conditions in the southeastern Carpathian Basin during the Last Glacial Maximum     

Patrick Ludwig  Milivoj B. Gavrilov  Milica G. Radaković  Slobodan B. Marković 《第四纪科学杂志》2021,36(8):1426-1435

We investigate the glacial climate conditions in the southeastern Carpathian Basin (Vojvodina, Serbia) based on the reconstruction of malacological palaeotemperatures and results from a high-resolution regional climate simulation. Land snail assemblages from eight loess profiles are used to reconstruct July temperatures during the Last Glacial Maximum (LGM). The malacological reconstructed temperatures are in good agreement with the simulated LGM July temperatures by the Weather Research and Forecast model. Both methods indicate increasing temperatures from the northwestern towards the southeastern parts of the study area. LGM aridity indices calculated based on the regional climate model data suggest more arid conditions in the southeastern parts compared with more humid conditions in the northwestern parts. However, for present-day conditions, the moisture gradient is reversed, exhibiting more humid (arid) conditions in the southeast (northwest). An explanation for the reversed LGM aridity pattern is provided by an analysis of the prevailing wind directions over the South Banat district (Serbia). The prevailing moist northwesterly winds during summer are not able to compensate for the annual lack of moisture induced by the dry winds from the southeast that are more frequent during the LGM for the other seasons.  相似文献   

Sedimentology of a Late Quaternary lacustrine record from the south-eastern Carpathian Basin     

Christian Zeeden  Ulrich Hambach  Nicole Klasen  Peter Fischer  Philipp Schulte  Janina J. Nett  Daniel Veres  Igor Obreht  Wei Chu  Maria Papadopoulou  Finn Viehberg  Frank SchÄBitz  Milivoj B. Gavrilov  Slobodan B. MarkoviĆ  Andreas VÖTT  Frank Lehmkuhl 《第四纪科学杂志》2021,36(8):1414-1425

The Upper Pleistocene geoarchives in the south-eastern Carpathian Basin are represented predominantly by loess–palaeosol records. In 2015, a 10 m sediment core composed of clay-rich lacustrine sediments was recovered by vibracoring a dry lake basin located between the Vršac Mountains (Serbia) and the Banat Sands in the south-eastern Carpathian Basin; a location relevant for placing regional archaeological results in a palaeoenvironmental context. Here, we present results from geoelectrical prospection and a lithostratigraphic interpretation of this sequence supported by a detailed granulometric study supplemented by ostracod analysis. An age model based on luminescence dating is discussed against sedimentological proxy data and its implication for palaeoenvironmental change. The cores show a stratigraphy of lighter ochre-coloured and darker greyish sediment, related to the deposition of clay and silt trapped in an aquatic environment. Geophysical measurements show ~20 m thick lacustrine sediments. The grain-size distributions including the variability in fine clay are indicative of a lacustrine environment. Fine particles were brought into the depositional environments by aquatic input and settled from suspension; also, direct dust input is constrained by grain-size results. Riverine input and aeolian dust input interplayed at the locality.  相似文献