Strato-mesospheric ozone and IMF sector boundary

Summary We find no effect of the interplanetary magnetic field(IMF) sector boundary crossing in ozone at altitudes ranging from the middle stratosphere(10 hPa) to the lower mesosphere(0.4 hPa) at middle latitudes(40°–60° N), based on winter data over the period of December 1979–December 1982.

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Резюме Мы не нaшлu нuкaко о эффекma nересеченuя секmорноŭ рaнuцы межnлaнеmно о мa нumно о nоля в озоне в облaсmu высоm меж?rt;у сре?rt;неŭ сmрamосфероŭ(10 Пa) u нuжнеŭ мезосфероŭ(0,4 Пa) нa сре?rt;нuх шuроmaх(40°–60° с.ш.), nрuменяя зuмнuе ?rt;aнные зa nерuо?rt; ?rt;екaбрь 1979 – ?rt;екaбрь 1982 .

     

Long-term variation of the semi-annual wave maxima in geomagnetic activity

Summary The time variations of the amplitudes and phases of the semi-annual variation in geomagnetic activity, characterized by the linear planetary index aa, have been analysed for the period 1868–1985. The results provide qualitative confirmation of Murayama's conclusions [13] about the systematic f phase in dependence on the changes in the level of solar activity and give support to Russel-McPherron's mechanism [16] concerning the effect of the predominant polarity of the interplanetary magnetic field. A distinctly expressed variation of the phase differences in the course of the sunspot cycle and of the 22-year cycle, and specific variations related to the sequence of four consecutive cycles have been established, as well as a well-defined 90-year period, all of them as a reflection of analogous variations in solar activity. The variations of the phase differences observed around the equinoxes can be explained by the combined effect of the mechanisms of the axial and equinoctial hypothesis. It is assumed that a displacement of the maxima of the semi-annual variation to dates after the equinoxes will be observed in the ascending parts and a reverse displacement towards the equinoxes and earlier dates in the desccending parts of the following sunspot cycles 22 nad 23.On leave from the Geophysical Institute of the Bulgarian Academy of Sciences, Akad. G. Bonchev Str. bl. 3, Sofia 1113, Bulgaria.     

Geomagnetic activity as a possible cause of changes in the middle atmosphere and troposphere; observations made in Prague in the years 1932–1987

Summary A possible relation between the 10-day, 1-month, and 2-month geomagnetic as well as solar activity, characterized by Kp and Wolf's number R, and temperatures measured at the Prague-Klementinum meteorological station in January–February of the years 1932–1987 was sought. It was found that:1) Kp correlates with the temperature in Prague better than Wolf's number R.2) If the QBO phase is taken into account, the correlations improve.3) Even if the correlations improves with increasing length of the subintervals into which the individual winter periods (January-February) were derived, their statistical significance declines.     

Paleogeothermal gradient in the boskovice furrow

Summary A coalification data set from the first seam of the Rosice-Oslavany coal district in the Boskovice furrow was used to estimate the temperature gradient prevailing within the furrow during Autunian sedimentation. An appreciable scatter of the data reflects the complicated history of the sedimentary region. The northern part of the district displays a higher degree of coalification. The results of the evaluation suggest that the region ceased to subside in the upper Autunian, and that the extent of the post-Autunian erosion does not exceed 500 metres. This version of the burial history, which is consistent with geological data, yields a temperature paleogradient of 76 mK/m for the northern part and of 72 mK/m for the southern part of the district. The gradients estimated are higher than those prevailing during the Carboniferous sedimentation in the Central Bohemian Basin (45 – 53 mK/m), lower than values found for the Ostrava Formation in the Upper Silesian Basin during its Namurian A sedimentation (about 95 mK/m), but comparable with values evaluated for the Karviná Formation of the same basin deposited during the Namurian B - C and Westphalian A (60 – 77 mK/m).Dedicated to the Memory of Professor Karel P     

Computation of Synthetic Seismograms in 2-D and 3-D Media Using the Gaussian beam Method

The Gaussian beam method is applied to vertical seismic profiling in 2-D and 3-D models. A simple approach to the computation of Gaussian beam seismograms in the vicinity of structural interfaces is proposed. The effects of (a) the radiation pattern of a point source, (b) non-causal attenuation, (c) transverse inhomogeneities in synthetic seismograms are studied on numerical examples.     

Sunspot indices characterizing the 11-year cycle as a whole and their relationship to the analogous indices of geomagnetic activity

Summary Sunspot indices characterizing the 11-year cycle as a whole were determined on the basis of Wolf's sunspot numbers and their total area as well as on the basis of the primary physically indices of the spot-generating activity of the Sun.Their interrelationship is shown and their relationship to the indices of geomagnetic activity aa and C_i is examined. It is shown that under high solar activity a certain saturation of the Earth's magnetosphere occurs and that the variations of geomagnetic activity correlate with the variations of the global sunspot indices (Wolf number and total area) but correlate but slightly with the primary physically sunspot indices.

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u u n¶rt;;u nm u uuu nu u¶rt;; nmaoam ¶rt;;mmu q, n¶rt;; u¶rt;;u nm, aamuu -mu u . aaa u aua u u u mu u¶rt;;a ¶rt;;a¶rt;;um amumu aa u _i. aa, m nu amumu mynam am aum u m auauu ¶rt;;a¶rt;;umo amumu um auauau ¶rt;; u¶rt;; nm (u a, aa na¶rt;), a um uuu nuu u¶rt;u nm.

     

Scattering by nonspherical particles and optical properties of Martian dust

Ultraviolet spectral reflectance data obtained from the Mariner 9 during the 1971 Mars dust storm were analyzed at two wavelengths to deduce the complex index of refraction of Martian dust. Martian dust particles were considered to be irregularly shaped and randomly oriented nonspherical particles. The analysis shows that the Mariner 9 data are consistent with the scattering by irregular particles with an index of refraction m = 1.59 ? 0.0015i at λ = 0.305 μm and m = 1.55 ? 0.004i at λ = 0.268 μm. Both the real and the imaginary parts of refractive index found are considerably smaller than previously reported results using a spherical shape model for Martian dust particles.     

Ccd Photometry of the Neglected Contact Binaries V344 Lac and V1191 Cyg

New photoelectric and CCD observations of the eclipsing contact binary systems V344 Lac and V1191 Cyg are presented and analyzed. All available times of minimum light were used to study period changes of the systems and determine up-to-date ephemerides. The orbital period of V1191 Cyg is found to be increasing at a very fast rate. The photometric elements were determined using the new light curve, radial-velocity curve and broadening function fitting code ROCHE.     

Cosmic gamma-ray emission and comet collisions with compact stars

The probability that γ-ray bursts may be generated by the infall of comet-like objects on the neutron stars, as recently proposed by Harwit and Salpeter (1973), is reexamined. Although hypothetical cometary clouds around the parent star may survive the supernova outburst virtually untouched, the frequency of γ-outbursts due to the comet impact on the neutron star or white dwarf is only about 10^?3 of the observed occurrence. A considerably higher rate of comets passing per year at critical periastron distance must be assumed if the γ-ray outbursts are to be due to the collision of coments with compact stars.     

Triaxiality of Halley's Comet

There are many aspects of observational evidence that cometary nuclei have irregular or nonspherical shape. The triaxial figure of the Halley's Comet nucleus is a well known fact. Therefore, the nucleus shape plays a significant role in consideration of the formation and evolution of comets and several attempts have been made to explain their nonsphericity. These studies were mainly based on the random-walk schemes for the aggregation processes. Although some results indeed lead to irregularities and deviation from sphericity, the spherical or irregular shape seem to be prevailing results. On the other hand the triaxial figure can be formed by the tidal and rotational forces. Thus, the assumption that the shape of the cometary nucleus due to some of these effects is in principle acceptable. In here assumed scenario already evolved cometary nucleus is situated as a satellite in the gravitation field of a planetary-like body. Since the rigidity of the nucleus is low, it may be easily transferred in the state of a synchronous satellite and in its shape could be imprinted the dynamical effects from this epoch. Here presented results indicate, that such a possibility should be seriously considered. The theory of this process is applied to the nucleus of comet Halley. It is shown, that the nucleus might be synchronously orbiting around a planetary-like hypothetical body with a period of 0.7 days. The minimal bulk tensile strength of the cometary material of about 10² N m^–2 is estimated.