Effect of mesoscale atmospheric vortex processes on the upper atmosphere and ionosphere of the Earth     

V. G. Bondur  S. A. Pulinets 《Izvestiya Atmospheric and Oceanic Physics》2012,48(9):871-878

The mechanisms of incipience and intensification of dangerous atmospheric vortex processes such as tropical cyclones (TCs) and their interaction with the Earth’s ionosphere are considered. Different models of TCs are analyzed, including models taking into account the ionization processes. The mechanisms taking into account the spiral field of velocities during TC formation are analyzed, as are the physical mechanism that explains the statistical correlation between short-term variations in galactic cosmic rays (Forbush decreases) and the frequency of incipience and the intensification of TCs. It is shown that such an effect is conditioned by a decrease in the ion-production rate during Forbush decreases against the tropopause and, hence, a decrease in the temperature upon the top of the ionosphere altitude because of a decrease in the latent heat release due to water-vapor condensation on the newly formed ions. This process leads to an increase in the temperature difference between the ocean surface and the top level of TCs and, respectively, to the intensification of vertical convection, which results in cyclone intensification. It is concluded that the study of these mesoscale vortex processes requires taking into account not only the hydrodynamical features of these formations, but also their thermodynamical and electrodynamical properties. The results are important for the organization of studying and monitoring TCs with the use of spaceborne techniques.  相似文献   

Pitfalls of microseismic data inversion in the case of strong anisotropy     

Sergey Yaskevich  Georgy Loginov  Anton Duchkov  Alexandr Serdukov 《应用地球物理》2016,13(2):326-332

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Analytic properties of Hansen coefficients     

Sergey Yu. Sadov 《Celestial Mechanics and Dynamical Astronomy》2008,100(4):287-300

Hansen’s coefficients in the theory of elliptic motion with eccentricity e are studied as functions of the parameter η = (1 − e ²)^1/2. Their analytic behavior in the complex η plane is described and some symmetry relations are derived. In particular, for every Hansen coefficient, multiplication by suitable powers of e and η results in an entire analytic function of η. Consequently, Hansen’s coefficients can be in principle computed by means of rapidly convergent series in powers of η. A representation of Hansen’s coefficients in terms of two entire functions of e ² follows.   相似文献   

Electrostatic radiation of plasma in the upper ionosphere in the inhomogeneous geomagnetic field     

N. I. Izhovkina  A. T. Karpachev  I. S. Prutensky  S. A. Pulinets  Z. Klos  H. Rotkel 《Geomagnetism and Aeronomy》2009,49(8):1254-1256

It has been indicated that the spectrum of electrostatic waves in the ionospheric plasma depends on the geophysical conditions and solar wind parameters. The wave field measurements in the frequency band 0.1–10 MHz in the topside ionosphere were used to analyze the electrostatic instabilities of the plasma electron content (the APEX satellite experiment). A change of the sign of one magnetic field component at the geomagnetic equator can result in the formation of the large-scale irregular plasma structure with a decay of the natural electrostatic oscillations and vortices in unstable plasma. The plasma particle polarization drift from the region of decay of electrostatic oscillations and vortices can cause large plasma density and temperature gradients across the geomagnetic field. New vortices can originate at these gradients. This mechanism of plasma vortex formation and decay can be important for mass and energy convection in the topside ionosphere.  相似文献   

Approaches to studying the multiscale ionospheric structure using nanosatellites     

A. A. Chernyshov  D. V. Chugunin  M. M. Mogilevsky  I. L. Moiseenko  A. A. Ilyasov  V. V. Vovchenko  S. A. Pulinets  M. V. Klimenko  I. E. Zakharenkova  A. V. Kostrov  M. E. Gushchin  S. V. Korobkov 《Geomagnetism and Aeronomy》2016,56(1):72-79

Permanent variation in parameters affecting the key characteristics of the auroral ionosphere hinders the creation of a sufficiently accurate model for practical application within classical approaches describing quasi-stationary phenomena. The fractal approach for describing the properties of plasma in the auroral region has the following advantages: the results are versatile and the emergence of self-similar structures is nature-independent. Due to the self-similarity and fractality of ionospheric structures, it will suffice to have a few measurements within a characteristic scale; therefore, it is necessary to obtain a series of simultaneous measurements at intervals of tens of meters to tens of kilometers to describe the spatial and temporal distribution of inhomogeneities in the ionospheric plasma. Small and relatively low-cost satellites (the socalled cubesats) are supposed to be used to check whether the fractal approach can be applied to study the inhomogeneous structure of the ionosphere, including with artificial heating. The satellites should be located at different distances from each other to span the scales ranging from the inertial length of electrons to the inertial length of O⁺ ions. For each satellite, it is supposed to measure the variations in plasma density and electric and magnetic fields.  相似文献   

Atlantic Multidecadal Oscillation and Northern Hemisphere’s climate variability   总被引：1，自引：1，他引：0  

Marcia Glaze Wyatt  Sergey Kravtsov  Anastasios A. Tsonis 《Climate Dynamics》2012,38(5-6):929-949

Proxy and instrumental records reflect a quasi-cyclic 50–80-year climate signal across the Northern Hemisphere, with particular presence in the North Atlantic. Modeling studies rationalize this variability in terms of intrinsic dynamics of the Atlantic Meridional Overturning Circulation influencing distribution of sea-surface-temperature anomalies in the Atlantic Ocean; hence the name Atlantic Multidecadal Oscillation (AMO). By analyzing a lagged covariance structure of a network of climate indices, this study details the AMO-signal propagation throughout the Northern Hemisphere via a sequence of atmospheric and lagged oceanic teleconnections, which the authors term the “stadium wave”. Initial changes in the North Atlantic temperature anomaly associated with AMO culminate in an oppositely signed hemispheric signal about 30?years later. Furthermore, shorter-term, interannual-to-interdecadal climate variability alters character according to polarity of the stadium-wave-induced prevailing hemispheric climate regime. Ongoing research suggests mutual interaction between shorter-term variability and the stadium wave, with indication of ensuing modifications of multidecadal variability within the Atlantic sector. Results presented here support the hypothesis that AMO plays a significant role in hemispheric and, by inference, global climate variability, with implications for climate-change attribution and prediction.  相似文献   

The surface chemistry of multi-oxide silicates     

Eric H. Oelkers  Sergey V. Golubev  Claire Chairat  Oleg S. Pokrovsky  Jacques Schott 《Geochimica et cosmochimica acta》2009,73(16):4617-6554

The surface chemistry of natural wollastonite, diopside, enstatite, forsterite, and albite in aqueous solutions was characterized using both electrokinetic techniques and surface titrations performed for 20 min in batch reactors. Titrations performed in such reactors allow determination of both proton consumption and metal release from the mineral surface as a function of pH. The compositions, based on aqueous solution analysis, of all investigated surfaces vary dramatically with solution pH. Ca and Mg are preferentially released from the surfaces of all investigated divalent metal silicates at pH less than ∼8.5-10 but preferentially retained relative to silica at higher pH. As such, the surfaces of these minerals are Si-rich and divalent metal poor except in strongly alkaline solutions. The preferential removal of divalent cations from these surfaces is coupled to proton consumption. The number of protons consumed by the preferential removal of each divalent cation is pH independent but depends on the identity of the mineral; ∼1.5 protons are consumed by the preferential removal of each Ca atom from wollastonite, ∼3 protons are consumed by the preferential removal of each Mg or Ca atom from diopside or enstatite, and ∼4 protons are consumed by the preferential removal of each Mg from forsterite. These observations are interpreted to stem from the creation of additional ‘internal’ adsorption sites by the preferential removal of divalent metal cations which can be coupled to the condensation of partially detached Si. Similarly, Na and Al are preferentially removed from the albite surface at 2 > pH > 11; mass balance calculations suggest that three protons are consumed by the preferential removal of each Al atom from this surface over this entire pH range. Electrokinetic measurements on fresh mineral powders yield an isoelectric point (pH_IEP) 2.6, 4.4, 3.0, 4.5, and <1, for wollastonite, diopside, enstatite, forsterite, and albite, respectively, consistent with the predominance of SiO₂ in the surface layer of all of these multi-oxide silicates at acidic pH. Taken together, these observations suggest fundamental differences between the surface chemistry of simple versus multi-oxide minerals including (1) a dependency of the number and identity of multi-oxide silicate surface sites on the aqueous solution composition, and (2) the dominant role of metal-proton exchange reactions on the reactivity of multi-oxide mineral surfaces including their dissolution rate variation with aqueous solution composition.  相似文献   

Unique variations of the total electron content in the preparation period of Haitian earthquake (M7.9) on January 12, 2010     

S. A. Pulinets  K. G. Tsybulya 《Geomagnetism and Aeronomy》2010,50(5):686-689

Variations of the total electron content according to the index IONEX IGS in the period of preparation of the earthquake in Haiti (M7.9) on January 12, 2010, are considered. The situation is exceptional owing to the unique position of the island of Haiti relative to the structure of the ionosphere over the Caribbean Sea: the ionospheric region over Haiti is in the trough formed by the northern slope of the equatorial anomaly and additional maximum formed at latitudes of approximately 30° N within this longitudinal interval. Distortion of the shape of the equatorial anomaly, total decrease in the electron content in the equatorial anomaly a few days prior to the earthquake, increase in the electron concentration directly over the earthquake epicenter a few days prior to the earthquake, increase in the additional maximum at latitudes of ∼30° N, and formation of an additional maximum in the Southern Hemisphere in the region conjugated to the additional maximum in the Northern Hemisphere in the periods of its intensification are observed. The configuration of the equatorial anomaly is restored after the earthquake.  相似文献   

A global isostatic gravity model of the Earth   总被引：3，自引：0，他引：3  

Mikhail K. Kaban  Peter Schwintzer  & Sergey A. Tikhotsky 《Geophysical Journal International》1999,136(3):519-536

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On the fate of processed matter in dwarf galaxies     

Sergey A. Silich  & Guillermo Tenorio-Tagle 《Monthly notices of the Royal Astronomical Society》1998,299(1):249-266

Two-dimensional calculations of the evolution of remnants generated by the strong mechanical energy deposited by stellar clusters in dwarf galaxies ( M  ∼ 10⁹–10¹⁰ M⊙) are presented. The evolution is followed for times longer than both the blowout time and the presumed span of energy injection generated by a coeval massive stellar cluster. The remnants are shown to end up wrapping around the central region of the host galaxy, while growing to kiloparsec-scale dimensions. Properties of the remnants such as luminosity, size, swept-up mass and expansion speed are given as functions of time for all calculated cases.   The final fate of the swept-up galactic gas and of the matter processed by the central starburst is shown to be highly dependent on the properties of the low-density galactic halo. Superbubbles powered by star clusters, with properties similar to those inferred from the observations, slow down in the presence of an extended halo to expansion speeds smaller than the host galaxy escape velocity. Values of the critical luminosity required for the superbubbles to reach the edge of the galaxies with a speed comparable to the escape speed are derived analytically and numerically. The critical luminosities are larger than those in the detected sources, and thus the superbubbles in amorphous dwarf galaxies must have already undergone blowout and are presently evolving into an extended low-density halo. This will inhibit the loss of the swept-up and processed matter from the galaxy.  相似文献