Connection between the upper ionospheric region of VLF chorus occurrence and the plasmapause position     

František Jiříček  Pavel Tříska  O. A. Maltseva  E. E. Titova  T. A. Yakhnina  Reviewer S. Fischer 《Studia Geophysica et Geodaetica》1986,30(4):404-410

Summary The occurrence zone of the VLF chorus in the upper ionosphere appears at L-shells lower than plasmapause position L_pp; with increasing geomagnetic activity the spatial dimension of the zone diminishes, its upper boundary being shifted in correspondence with the plasmapause position, the lower remaining practically without change(L=2.0÷2.5). Calculations of propagation paths have shown that the similarity of the VLF chorus spectrum at different upper-ionospheric latitudes as well as the large spatial dimension of the zone of observation can be explained as special features in the propagation of VLF waves from an equatorial source, starting in the vicinity of the plasmapause with different initial normal angles.

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a umauu u ana amu L-, u L_pp (L_pp — nu nana); uu aum amumu nmam a am, nu aua am mmmuu uu nu nana, a u mam namuu u(L=2.0÷2.5). am mamu naam, m n¶rt;u nm a au uma u, ma a nmam ama a¶rt;u, m m mu anmau m amua umua, an amu nana, uu au au.

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On the possibilities of observing ballistic plasma wave processes in the magnetosphere     

E. D. Poezd  V. N. Oraevskij  Vladimír Fiala  Pavel Tříska  Reviewer S. Fischer 《Studia Geophysica et Geodaetica》1987,31(2):197-212

Summary The conditions are studied under which ballistic effects of transmission of waves through opacity barriers can be observed in magnetospheric experiments on board satellites. The mechanism of this effect consists of the regeneration of the radiation beyond the barrier by resonance electrons, modulated by a quasimonochromatic wave incident and reflected from the barrier. Ballistic processes in continuously inhomogeneous plasma are studied. Detailed analysis has been carried out for a barrier with a parabolic density profile. Recommendations are presented as to experimental procedures in circumterrestrial space and data processing. The possibilities are studied of observing ballistic effects in the course of active space experiments with sources of intensive broadband turbulence such as beam of charged particles, injected into the magnetosphere.

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¶rt;a u, nu m ¶rt; nmu num aum na m a¶rt;am aumuu m n¶rt;u a namu, au m mum auu uu a a au mau, n¶rt;uau auamu , na¶rt;a a a u maa m . am aumuu n na¶rt;¶rt; na. ma u n¶rt; ¶rt; aa naauu nu nmmu. a ¶rt;auu n n¶rt;u numa nmam u n am ¶rt;a. ¶rt;am m a¶rt;u aumuu m ¶rt; amu uu num umuau umu un mmmu, mauu, a nu a amu umu aum.

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Pressure variability during medium-temperature metamorphism of meta-pelites     

K.B. Kepezhinskas 《Lithos》1973,6(2):145-157

A study is made of a complex where the metamorphis zonation with respect to pressure does not coincide with the temperature zonation. The possibility of estimating the P-T conditions of metamorphism is shown on the basis of quantitative statistical characteristics in the distribution of critical minerals, combined with data on the bulk rock chemistry.An example is also given of metamorphic zonation in which a general trend of decreasing pressure is observed in the direction of increasing temperature.Based on schematic P-T diagrams for quartz and muscovite-bearing metapelites the conditions of metamorphism in the middle-temperature region can be examined in detail and the best ways of subdividing corresponding facies into subfacies can be determined.Results are presented concerning the dependence of the compositions of a number of minerals of common parageneses on pressure. Criteria are suggested for the estimation of conditions of metamorphism based on the chemical characteristics garnets and biotites.  相似文献   

Interpretation and possibilities of applying LHR frequency determined from satellite VLF measurements in middle geomagnetic latitudes     

Jaroslava Bošková  František Jiříček  Pavel Tříska  Reviewer S. Fischer 《Studia Geophysica et Geodaetica》1982,26(4):373-380

un nmu a ¶rt;u ¶rt;am ¶rt; mm u a uuuu¶rt; a () a na. m nm, u , ¶rt;um a amm mmu nmua a m m na ¶rt; mum uaum um (2uamm m f_H u na amm m f_N. uam mm n au ¶rt; amm , ¶rt;mum amu¶rt; f _N ² f _H ² u f _H ² f _N ² . a m a n¶rt;um umnmau aamumu auauu amm n u nmu a¶rt;u.  相似文献   

Non-steady kinematic dynamo model with spiral convection     

Pavel Hejda  Reviewer G. Siráň 《Studia Geophysica et Geodaetica》1981,25(4):366-375

Summary The stability of steady states, the evolution of the magnetic field and possible changes of the magnetic field under small changes of velocity are studied on a non-stationary solution of a kinematic dynamo model.  相似文献   

The extent and intensity of the urban heat island in Iași city,Romania     

Lucian?Sf?c?Email authorView author&#;s OrcID profile  Pavel?Ichim  Liviu?Apostol  Adrian?Ursu 《Theoretical and Applied Climatology》2018,134(3-4):777-791

The study underlines the characteristics of the urban heat island of Ia?i (Ia?i’s UHI) on the basis of 3 years of air temperature measurements obtained by fixed-point observations. We focus on the identification of UHI development and intensity as it is expressed by the temperature differences between the city centre and the rural surroundings. Annual, seasonal and daily characteristics of Ia?i’s UHI are investigated at the level of the classical weather observation. In brief, an intensity of 0.8 °C of UHI and a spatial extension which corresponds to the densely built area of the city were delineated. The Ia?i UHI is stronger during summer calm nights—when the inner city is warmer with 2.5–3 °C than the surroundings—and is weaker during windy spring days. The specific features of Ia?i’s UHI bear a profound connection to the specificity of the urban structure, the high atmospheric stability in the region and the local topography. Also, the effects of Ia?i’s UHI upon some environmental aspects are presented as study cases. For instance, under the direct influence of UHI, we have observed that in the city centre, the apricot tree blossoms earlier (with up to 4 days) and the depth of the snow cover is significantly lower (with up to 10 cm for a rural snow depth of 30 cm) than in the surrounding areas.  相似文献   

The second most disastrous windstorm of the nineteenth century in the Czech Lands, 26-27 October 1870     

Brázdil  Rudolf  Stucki  Peter  Szabó  Péter  Dobrovolný  Petr  Řezníčková  Ladislava  Kotyza  Oldřich  Valášek  Hubert  Dolák  Lukáš  Zahradníček  Pavel  Suchánková  Silvie 《Theoretical and Applied Climatology》2018,132(3-4):1201-1216

Theoretical and Applied Climatology - One of the most disastrous windstorms to take place over the Czech Lands occurred on the night of 26/27 October 1870. It is here analysed through the use of...  相似文献   

Long-term variability of temperature and precipitation in the Czech Lands: an attribution analysis     

Jiří Mikšovský  Rudolf Brázdil  Petr Štĕpánek  Pavel Zahradníček  Petr Pišoft 《Climatic change》2014,125(2):253-264

Among the key problems associated with the study of climate variability and its evolution are identification of the factors responsible for observed changes and quantification of their effects. Here, correlation and regression analysis are employed to detect the imprints of selected natural forcings (solar and volcanic activity) and anthropogenic influences (amounts of greenhouse gases—GHGs—and atmospheric aerosols), as well as prominent climatic oscillations (Southern Oscillation—SO, North Atlantic Oscillation—NAO, Atlantic Multidecadal Oscillation—AMO) in the Czech annual and monthly temperature and precipitation series for the 1866–2010 period. We show that the long-term evolution of Czech temperature change is dominated by the influence of an increasing concentration of anthropogenic GHGs (explaining most of the observed warming), combined with substantially lower, and generally statistically insignificant, contributions from the sulphate aerosols (mild cooling) and variations in solar activity (mild warming), but with no distinct imprint from major volcanic eruptions. A significant portion of the observed short-term temperature variability can be linked to the influence of NAO. The contributions from SO and AMO are substantially weaker in magnitude. Aside from NAO, no major influence from the explanatory variables was found in the precipitation series. Nonlinear forms of regression were used to test for nonlinear interactions between the predictors and temperature/precipitation; the nonlinearities disclosed were, however, very weak, or not detectable at all. In addition to the outcomes of the attribution analysis for the Czech series, results for European and global land temperatures are also shown and discussed.  相似文献   

Optimization of ice cuttings transportation by cable-suspended core auger drills     

HONG Jialin  Pavel Talalay  Mikhail Sysoev 《东北亚地学研究》2014,(1):48-54

Ice cores contain an abundance of information about the Earth＇s climate in the past, and recovered from shallow drilling down to 300-350 m give sufficient information for reconstructing of the last climatic changes and for monitoring of pollution from human being. Cable-suspended core auger drills use an armored cable with a winch to provide power to the down-hole motor system and to retrieve the down-hole unit. Because of their lightweight, convenient transportation and installation, high penetration rates and low power consumption, core auger drills are widely used for shallow drilling in ice. Nowadays at least 14 types of auger electromechani- cal drills were designed and tested in different foreign and national glaciological laboratories. However, auger options were usually determined by experience, and the main parameters （ helix angle of the fights and rotational speed） are varied in a wide range from drill to drill. If parameters of auger are not chosen properly, poorly en- gineered drills had troubles with low efficiency of cuttings transportation, jam of ice cuttings, repeated fragmen- tation, cutters icing and stop penetration, abnormal power consumption, high rotation torques, and so on. Thus, this paper presents the method of optimization of iee cuttings transportation of cable-suspended core auger drill on the base of the theory of rotary auger. As the result, the optimal helix angle was determined correspond- ing to the rotational speed from the transportation efficiency point of view.  相似文献   

Hidden staircase signal in recent climate dynamic     

Pavel Belolipetsky  Sergey Bartsev  Yuliya Ivanova  Mikhail Saltykov 《Asia-Pacific Journal of Atmospheric Sciences》2015,51(4):323-330

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