First Results of DSD Measurement by Videodistrometer in the Czech Republic in 1998-1999     

Fišer  Ondřej  Schönhuber  Michael  Pešice  Petr 《Studia Geophysica et Geodaetica》2002,46(3):485-505

The first results of the almost one year drop size distribution (DSD) measurement in the Czech Republic are summarised in this study. The ESA-ESTEC 2D videodistrometer was used to measure the rain drop parameters. The average DSD is shown to be of the gamma type. One minute DSDs were evaluated to test the accuracy of analytical DSD models. Parameters of gamma distribution and exponential distribution functions were evaluated for the whole data set as well as for the various rain rate intervals. Regression technique and the method of moments were applied to estimate the parameters of DSD. It is shown that the parameter value strongly depends on the method of computation as well as on the rain type. Its average value is about 0.59 for the average (smooth) one minute DSD while an average value of un-smoothed DSD is 11.0 (moment method) or 5.4 (regression technique). The Joss's shape parameter and the Tokay-Short's parameter CS estimating roughly the rain type are also discussed (if CS>1, the event should be convective). The tendency of increasing numerical value of the CS parameter with the increasing rain rate was observed (the DSDs were distributed into classes respecting the rain rate value) and thus the idea of the convectivity occurrence bounded with the higher CS parameter value was supported. The study also compares the parameters of the average DSD with the averages of parameter values of all 4 183 one minute DSDs.  相似文献   

Chaotic transitions in resonant asteroidal dynamics     

S. Ferraz-Mello  J. C. Klafke  T. A. Michtchenko  D. Nesvorný 《Celestial Mechanics and Dynamical Astronomy》1996,64(1-2):93-105

The utilization of chaotic dynamics approaches allowed the identification of many modes of motion in resonant asteroidal dynamics. As these dynamical systems are not integrable, the motion modes are not separated and one orbit may transit from one mode to another. In some cases, as in the \31 resonance, these transitions may lead, in a relatively short time scale, to eccentricities so high that the asteroid may approach the Sun and be destroyed. In the \21 and \32 resonances these transitions are much slower and only indirect estimations of the time which is needed for a generic asteroid to leave the resonance are possible. It may reach hundreds of million years in the more robust regions of the \21 resonance and a time of the order of billions of years in those of the \32 resonance. These values are consistent with the observed depletion of the \21 resonance (only a few asteroids known while almost 60 asteroids are known in the \32 resonance).  相似文献   

Statistical field theory,volume 1: From brownian motion to renormalization and lattice gauge theory,volume 2: Strong coupling,monte carlo methods,conformal field theory,and random systems     

Roman Kotecký 《Astrophysics and Space Science》1992,187(1):163-163

  相似文献   

Систематические разности фундаментальных каталогов и метод равных высот     

Georgij Karský 《Studia Geophysica et Geodaetica》1959,3(3):227-231

  相似文献   

Quasibiennial oscillations of the north-south asymmetry     

O. G. Badalyan  V. N. Obridko  J. Rybák  J. Sýkora 《Astronomy Reports》2005,49(8):659-670

The north-south (N-S) asymmetry of the solar activity (A), which reflects differences in the behavior of the northern and southern hemispheres of the Sun, is studied using data on the brightness of the coronal green line, the total number and area of sunspots, and the net magnetic flux. The spatial and temporal distributions and correlations between the A values represented by these indices are considered. The characteristic time variations in A are similar for all the indices, on both long and short time scales. Quasibiennial oscillations (QBOs) can be traced in the asymmetries of all four indices. A detailed study of the QBOs is carried out based on spectral-variation and wavelet analyses. Long-term increases and decreases occur synchronously in the asymmetries of various indices and are much more pronounced in A than in the indices themselves. A negative correlation between the power of the QBOs and the asymmetry of A can be traced; it is most clearly manifest as a substantial diminishing of the QBOs during the mid-1960s, which coincided with an especially strong increase in A. Our analysis shows that the N-S asymmetry is probably a fundamental property that controls the coupling and degree of coincidence between the magnetic-field-generation mechanisms operating in the northern and southern hemispheres.  相似文献   

Multi-wavelength study of a high-latitude EUV filament     

Brigitte Schmieder  Yong Lin  Petr Heinzel  Pavol Schwartz 《Solar physics》2004,221(2):297-323

A large filament was observed during a multi-wavelength coordinated campaign on June 19, 1998 in the Hα line with the Swedish Vacuum Solar Telescope (SVST) at La Palma, in the coronal lines Fe ix/x 171 Å and Fe xi 195 Å with the Transition Region and Coronal Explorer (TRACE) and in EUV lines with the SOHO/CDS spectrometer and the hydrogen Lyman series with the SOHO/SUMER spectrometer. Because of its high-latitude location, it is possible to disentangle the physical properties of the Hα filament and the filament channel seen in EUV lines. TRACE images point out a dark region fitting the Hα fine-structure threads and a dark corridor (filament channel), well extended south of the magnetic inversion line. A similar pattern is observed in the CDS EUV-line images. The opacity of the hydrogen and helium resonance continua at 171 Å is almost two orders of magnitude lower than that at the Hi head (912 Å) and thus similar to the opacity of the Hα line. Since we do not see the filament channel in Hα, this would imply that it should also be invisible in TRACE lines. Thus, the diffuse dark corridor is interpreted as due to the coronal ‘volume blocking’ by a cool plasma which extends to large altitudes. Such extensions were also confirmed by computing the heights from the projection geometry and by simulations of the CDS and TRACE line intensities using the spectroscopic model of EUV filaments (Heinzel, Anzer, and Schmieder, 2003). Finally, our NLTE analysis of selected hydrogen Lyman lines observed by SUMER also leads to a conclusion that the dark filament channel is due to a presence of relatively cool plasma having low densities and being distributed at altitudes reaching the Hα filament.  相似文献   

Coronal Activity During the 22-Year Solar Magnetic Cycle     

Storini  Marisa  Sýkora  Július 《Solar physics》1997,176(2):417-430

The existence of a 22-year heliomagnetic cycle was inferred long ago not only from direct measurements of the solar magnetic field but also from a cyclic variability of a number of the solar activity phenomena. In particular, it was stated (a rule derived after Gnevyshev and Ohl (1948) findings and referenced as the G–O rule in the following) that if sunspot number Rz cycles are organized in pairs of even–odd numbered cycles, then the height of the peak in the curve of the yearly-averaged sunspot numbers Rz-y is always lower for a given even cycle in comparison with the corresponding height of the following odd cycle. Exceptions to this rule are only cycles 4 and 8 which, at the same time, are the nearest even cycles to the limits of the so-called Dalton minimum of solar activity (i.e., the 1795–1823 time interval). In the present paper, we are looking for traces of the mentioned G–O rule in green corona brightness (measured in terms of the Fexiv 530.3 nm emission line intensity), using data covering almost five solar cycles (1943–1994). It was found that the G–O rule seems to work within the green-line corona brightness, namely, when coronal intensity measured in an extended solar middle-latitude zone is considered separately from the rest of the solar surface. On the other hand, the same G–O rule is valid at the photospheric level, as the heliographic latitudinal dependence of sunspot numbers (1947–1984) shows.  相似文献   

Electron-microprobe dating of monazites from Western Carpathian basement granitoids: plutonic evidence for an important Permian rifting event subsequent to Variscan crustal anatexis     

F. Finger  I. Broska  B. Haunschmid  L. Hrasko  M. Kohút  E. Krenn  I. Petrík  G. Riegler  P. Uher 《International Journal of Earth Sciences》2003,92(1):86-98

Accessory monazites from 35 granitoid samples from the Western Carpathian basement have been analysed with the electron microprobe in an attempt to broadly constrain their formation ages, on the basis of their Th, U and Pb contents. The sample set includes representative granite types from the Tatric, Veporic and Gemeric tectonic units. In most cases Lower Carboniferous (Variscan) ages have been obtained. However, a much younger mid-Permian age has been recorded for the specialised S-type granites of the Gemeric Unit, and several small A- and S-type granite bodies in the Veporic Unit and the southern Tatric Unit. This distinct Permian plutonic activity in the southern part of the Western Carpathians is an important, although previously little considered geological feature. It appears to be not related to the Variscan orogeny and is interpreted here to reflect the onset of the Alpine orogenic cycle, with magma generation in response to continental rifting. The voluminous Carboniferous granitoid bodies in the Tatric and Veporic units comprise S- and I-type variants which document crustal anatexis accompanying the collapse of a compressional Variscan orogen sector. The Variscan magmas were most likely produced through the remelting of a subducted Precambrian volcanic arc-type crust which included both igneous and sedimentary reworked volcanic-arc material. Although the 2C errors of the applied dating method are quite large and typically ᆞ-20 Ma for single samples, it would appear from the data that the Variscan S-type granitoids (333-367 Ma) are systematically older than the Variscan I-type granitoids (308-345 Ma). This feature is interpreted in terms of a prograde temperature evolution in the deeper parts of the post-collisional Variscan crust. In accordance with recently published zircon ages, this study shows that the Western Carpathian basement must be viewed as a distinct "eastern" tectonomagmatic province in the Variscan collision zone, where the post-collisional crustal melting processes occurred ~20 Ma earlier than in the central sector (South Bohemian Batholith, Hohe Tauern Batholith).  相似文献   

Reanalysis of four NASA stratospheric particles     

I. Kapišinský  V. Figusch  A. Hajduk  J. Ivan  K. Iždinský 《Earth, Moon, and Planets》1994,64(3):273-280

Four stratospheric contaminants catalogued in the Cosmic Dust Catalogs published by the NASA Johnson Space Center (JSC) in Houston were reanalysed. The results are compatible with those obtained in JSC, however additional features have occurred in our chemical analyses and their interpretation is also discussed.  相似文献   

Skalnaté Pleso Astronomical Institute     

J. Sýkora 《Solar physics》1968,4(1):122-125

  相似文献