Spectra and polarization characteristics of geomagneticPc4 pulsations recorded at field station štrkovec

ama nm u nmam nuau aamumuuaum nau muna Pc4 n ¶rt;a u mauu m, a¶rt; a m m anam ¶rt;u amu u¶rt;a umu. n¶rt;a auum nu¶rt;a u anum¶rt; nau u u nuau aamumu mu ¶rt; u m aum amumu, u au uu m¶rt; naam. mam auam mamau amu nau Pc3 u Pi2 n ¶rt;a u mau ¶rt; u u.     

Current estimates of the Earth's principal moments of inertia

Summary The principal moments of the Earth's inertia and their differences have been computed and their actual accuracy estimated on the basis of the most recent values of the 2nd degree geopotential parameters (model GEM-T2) and of the parameter H in the precession constant. The contributions due to the zero frequency zonal term in the tidal potential have been determined.

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au m nmnmuaa 2- mnu (¶rt; GEM-T2) u naama nm nuu n¶rt; aua m uuu u u u amu u ¶rt;am u a mmu. u a¶rt; n¶rt; uu nm amu a a nuu nmuaa.

     

Deflections of the vertical on the territory of Europe from satellite data

amu n¶rt;ma u ma mum au n¶rt;¶rt; m unu¶rt;a, amu n u amu uu, u n nmu ¶rt;a [2]; ¶rt;am nu uum, n m uum ¶rt;um au mau u ma ¶rt; muu¶rt;a.     

A comment on the effect of discretization on dispersion

a mamumuu m, m n¶rt; u a¶rt;a au, um ¶rt;umuau. aam, m a au ¶rt;unu a¶rt;a au n ¶rt;umuauu u n¶rt; nu a an¶rt; a u uu aa ,¶rt; h a ¶rt;umuauu.     

Linear modelling in vertical ionospheric sounding

Summary Applying the methods of computing N(h) profiles to scalar product spaces provides a more general view of the differences between the individual ionospheric models, which enables a better selection of the optimum model.

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u n¶rt; m¶rt;uu ama N(h) nu nmama a nu¶rt;u anauam u ¶rt; a au ¶rt; m¶rt;u uu ¶rt;u, m nm nmm uam nmua ¶rt;.

     

Equations of motion of the moon retaining higher harmonics in the force function

u u u u uu smu um ¶rt;um ¶rt; a, s¶rt;a ¶rt;a ¶rt;u suu (n — mn, k — n¶rt;): saumauo n u: n=2, k=0; n=2, k=2; n=3, k=0, 1, 2, 3; n=4, k=0; n=4, k=3; saumau n : n=2, k=0; n=2, k=2; saumau n a: n=2, k=0.

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Dedicated to Prof. RNDr. Emil Buchar, DrSc., Corresponding Member of the Czechoslovak Academy of Sciences, on the Occasion of His 75^th Birthday     

On one possible type of upper cyclogenesis

Summary Based on model considerations it is shown that, under certain assumptions, upper cyclogenesis may be expected in the region of the auroral oval as a result of heat released at the time energetic particles of extraterrestrial origin penetrate into the lower stratosphere or even troposphere.

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a auu ¶rt; a¶rt;u naa, m nu m n¶rt;nu u¶rt;am u amu aa aa mam ¶rt;u mna nuu muu amu nu¶rt;u u mam uu mn.

     

Analysis of the magnetometric vibration method

n¶rt;m mu ¶rt; mu uau aumma. mu aum u mu u m u mu auauu m¶rt;a. u¶rt;m u naam nm nmmuna uau aumma.     

Precipitation of electrons after geomagnetic substorms

Summary Precipitating electrons E_e>10 keV and E_e>30 keV and protons E_p=150 to 300 keV are analyzed using data obtained from the low-altitude polar-orbiting satellite Interkozmos-17 after the magnetic storm of December 2, 1977. On December 3, an isolated substrom occurred, and strong electron precipitation was observed in the midnigt sector, while the sequence of substorms of December 5 expanded its longitudinal extent from 22 MLT through the morning to 12 MLT. The different character of the precipitation, in the two cases mentioned, is discussed in relation to the changes of conditions for the generation of cyclotron instability as well as to the effect of particle injection. Proton precipitation occurred only in the night sector, most probably just inside the plasmapause.

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¶rt; aau nau m E_e>10 u E_e>30 u nm E_p=150–300 n uu n uuma nmua n um m-17 n aum u 2. ¶rt;a 1977. 3. 12. nua uuaa u u nau m aumua m mo u. a n¶rt;amm 5. 12. nua auu ¶rt;m umaa, m m nau, a u m 22 MLT mu m ¶rt; 12 MLT. a aam nau nu¶rt; ¶rt; a ¶rt;am aa uu u ¶rt; uu um mumu u ¶rt;mu uuu amu. nau nm n¶rt;u m m u m a naana mu naa.

     

The four primary geodetic parameters

Summary The four primary geodetic parameters defining the geodetic reference system are discussed from the point of view of their physical meaning and current estimation of their actual accuracy. The geopotential scale factor has been treated as the primary geodetic parameter defining the Earth's dimensions.

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¶rt;am m nu¶rt;uu naama, n¶rt;u¶rt;u um mumu, mu u uu a u mmu. ama amnmuaa ¶rt;am am nu¶rt;u naama, n¶rt; a u.

     

Theoretical wiese induction vectors for a three-dimensional prism in the vicinity of a vertical contact

Summary With the use of the method of boundary integral equations, a stationary approximation of the magnetotelluric field for a three-dimensional prism located in the vicinity of a vertical contact of two quarterspaces, whereby the applied electric field is oriented parallel with the vertical boundary, is solved. In combination with the solution for the perpendicular orientation of the exciting electric field, the theoretical Wiese induction vectors for three positions of the 3-D prism are calculated. It was shown that the centre of divergence of the Wiese vectors is displaced from the epicentre of the prism, namely, if the prism is close to the vertical boundary.

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nu m¶rt;a ¶rt;a u¶rt;a au n¶rt;maa mauaa annuau u nu¶rt; mam u¶rt; ama a¶rt;ummu¶rt; n ¶rt; nu, an uu mua¶rt; mama ¶rt; mmnmam. ¶rt;a mu n n¶rt;na¶rt;am ana naa mua ¶rt;au. uau aamua¶rt; a a aauua a nn¶rt;u ana¶rt; ¶rt;a¶rt; n ¶rt;aa m uum mmuu u¶rt;u m u ¶rt; m nu m nu. aa, m m a¶rt;u m u mum numa nu, ¶rt;¶rt;a nua nuaam mua ¶rt;au.

     

Determination of the gravitational effect of extensive spherical laminae (platforms) using generalized Talwani's method

u uuuuaumau uu u m, ¶rt;u a mumau nmu a u nmu mau u nmmu. au n¶rt; nuau ¶rt;mam u u m. nua m¶rt; m u m¶rt;a aau (1960) ¶rt; uu .     

Palaeointensity of the geomagnetic field during upper cainozoic derived from palaeo-slags and porcellanites in north Bohemia

Summary Porcellanites and palaeo-slags from North Bohemia are natural materials which can be used to derive the palaeomagnetic directions and palaeointensity of the geomagnetic field active at the time of caustic alteration. The origin of these rocks, called erdbrands, was due to the caustic alteration of predominantly pelitic sediments as a result of underground fires conditioned by spontaneous ignition of coal seams. The caustic alteration occurred during the Upper Pliocene to the Quaternary. Three procedure based on the methods by Thellier and Nagata are presented in the paper. The newly developed apparatus MAVACS (Magnetic Vacuum Control System) was used for the thermal demagnetization of samples. A procedure based on multi-component analysis was also proposed and tested. Besides some methodic results, it was found that the geomagnetic field intensity varied during the respective period within the limits of 48%±4% to 154%±32% of the present geomagnetic field intensity.

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aum u na au a mumuu uu n¶rt;mam nu¶rt; amua, m n¶rt;¶rt;um ¶rt; ¶rt;u naaum anau u naumumuaum n, ¶rt;m amu uu. mu n¶rt;, aa ¶rt;a¶rt;, uu n¶rt; uu amu uu num num a¶rt; n¶rt; ¶rt;mu aau . amu uu u m nu¶rt; m nua ¶rt; mmu nu¶rt;a. am n¶rt; mu umnmau nua, n¶rt;¶rt;u ¶rt; ¶rt;u naumumu, nuau a m¶rt; u aama. a aamaa annaama MAVACS (Magnetic Vacuum Control System) a unaa ¶rt; mu aauuau ¶rt; amu aa. n¶rt; u n n¶rt;¶rt;, a a munm aau amuauu. nu m¶rt;uu au, ma ma, m umumaum n u¶rt; nu¶rt; a n¶rt;a 48%±4%-154%±32% au umumu aum n.

     

On free nutation of the rotation vector of a rigid body

aam, m ¶rt;-mau ¶rt;uu a ma au am m¶rt; ma m unmuu m m. ¶rt;a, u a u unmuu annuuam, m am n una u 0,1 u a u ammuuu ¶rt;mau aa m m.     

On the role of vertical resolution in the analysis of shallow convective fields

Summary The present paper is an attempt to demonstrate the fact that misleading information about the thermodynamic structure of shallow cumulus fields is obtained when standard isobaric level (SIL) data input is used. The 1-D cumulus model serves as the main tool of examination and the reference input data are those of significant levels (SL) in soundings. The computed cloud tops (SIL) exceeded (SL) tops in nearly 80% of the cases and the excesses are more than 1 kilometre in 25% of the cases. Some discrepancies were also found in potential stability analysis. The local changes in equivalent potential temperature may be seriously affected and even falsified. The important role of high resolution in studies of mesoscale phenomena was again accentuated.

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mam mum ¶rt;aam, m u am u¶rt; ¶rt;a unam ¶rt;a ma¶rt;am uauu (SIL), m num uauu m¶rt;uau mm mu n. ¶rt;m, una nu u¶rt;auu, m ¶rt;a ¶rt; aa, a am n ¶rt; au unm ¶rt;a au ¶rt;aa. auma u a ¶rt; SIL n¶rt;m n au 80% a, a 25% a ¶rt;a a 1 . au ma ma nu aau nmua mumu. aQj uu uam nmua mnam m m aum ua. n¶rt;uam aa aua nmu nu uuu u a.

     

Deformation properties of the lithosphere derived from data on recent crustal movements of the earth

aamuam a¶rt;aa ¶rt;uu ¶rt; m u¶rt;mu, uau n¶rt; uu mua ¶rt;uu a uau u . a auu au mmuu mam ¶rt;au mua ¶rt;uu ¶rt;am m am ¶rt; ¶rt;au ma um.     

Three-dimensional modelling convection in the earth's mantle: Influence of the core-mantle boundary

Summary Mass heterogeneities in the Earth's mantle are derived from the spherical expansions of the core-mantle boundary topography, the surface topography and the external gravity field. The obtained density distribution provides the body forces driving the convection in the mantle. Assuming Newtonian rheology, the convection is modelled by solving the Stokes problem in the region extending from the top of the D"-layer to the base of the lithosphere. The derived model of mantle motions favours the concept of whole-mantle convection; its pattern connects the shape of the core-mantle boundary with surface tectonics.

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¶rt; aauu nmmu amuu u. am u¶rt; ¶rt;a una uum au ¶rt; ¶rt;aumau¶rt; n, a nmu u u nmu ¶rt;au amu-¶rt; ¶rt; n uu u. u, mmmu n an¶rt;u nmmu, am u. am m uu n¶rt;u amu ¶rt; ¶rt;au D" u u ¶rt;au um nu n¶rt;nuu, m amua amuu a¶rt;am mau m u¶rt;mu. a ¶rt; ¶rt;uu aama m, m ¶rt;u u u¶rt;u nmu n¶rt;m amu u am ¶rt;au ¶rt; amu u ¶rt; nm mmu.

     

Results of the earth-tide measurements at the Pecný station (CSSR)

¶rt;mam mam a¶rt;u, m u a nuu mauu nu¶rt; 1970–1977. nauaumGs 11 No 131, 201 uGs 15 No 228. a¶rt; ¶rt;uam mauau ¶rt;u um. ¶rt;uu au naam nuu nu¶rt; ma. 2,uuu au ma. 3.

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Paper presented at the IUGG XVII Plenary Meeting, Canberra, Dec. 1979.     

Spherical harmonic analysis and Fourier transformation

Summary The paper deals with the computation of spherical harmonic coefficients from surface measurements of the magnetic or gravity field of the Earth when the measurements are distributed regularly. The Fourier representation of associated Legendre functions which this procedure makes use of, then enables the harmonic analysis to be transformed to Fourier analysis which has better numerical properties.

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ama na ama uu uu uum n nm uu aum uuaumau n u a, ¶rt;a mu uu an ammu ma. ¶rt;mau n a¶rt; , m unm mm n¶rt;¶rt;, nm nmauu aau naam aau , m a¶rt;am uu uumu mau.

     

Day-time ionospheric disturbances of corpuscular origin in the midlatitudeD-region

¶rt;m uu nau mu m a nu a¶rt;u ¶rt; D-amu u. a¶rt; m nu u u. u¶rt;a a a mu nma u nma mu m (20 ¶rt; 150 ).