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1.
To study the effects of strong scattering on elastic waves, spatial fluctuation and scattering attenuation ofP waves were examined by laboratory experiments for 2-D models of random media approximately characterized by a triangular correlation function in the range of 2<ka<33, wherek is the wave number anda is the correlation distance of the heterogeneities, i.e., the heterogeneity size. The results obtained are as follows: (1) Forka>10, both the intensity and the correlation distance of the amplitude fluctuation are approximate for any phase of theP-wave train. The correlation distance nearly agrees with the heterogeneity size. These fluctuation properties are quite consistent with the theoretical prediction by the forward-scattering approximation. (2) For 3<ka<6, the fluctuation intensity becomes stronger in later phases of theP-wave train. This shows that scattering is approximately isotropic, and therefore, the scattered energy increases with time within theP-wave train. The correlation distance of the amplitude fluctuation disagrees with the heterogeneity size, and it shows a frequency-dependent property decreasing from 7a to 4a with the increase ofka from 3 to 6. These properties for 3<ka<6 have not yet been predicted theoretically. (3) Forka<3, though the fluctuation is considerably smaller compared with that ofka>10 and 3<ka<6, the fluctuation property is considered similar to that of 3<ka<6. (4) The observed scattering attenuation,Q –1, increases withka forka<3, has a peak aroundka=35, and then decreases withka. (5) When min = 15° and = 0.075, the theoreticalQ –1 curve, predicted by the approximate theory of Wu, roughly matches the observedQ –1 values, where min is the minimum scattering angle measured from the propagation direction of theP waves and is the rms of fractional velocity fluctuation. This suggests that the energy scattered in the range of >15° is lost from theP waves, while the energy scattered in the range of <15° is retained; and that the approximate theory overestimates by about three times the value of the model media used owing to the neglect of multiple scattering. (6) When the size of velocity heterogeneities responsible for forward scattering at 3<ka<6 is estimated from the min value of 15° on the basis of Wu's theory, it nearly agrees with the correlation distance for the initial phase of theP-wave train.  相似文献   

2.
Summary Review has been made of the first results and perspectives of investigations in geophysics and bordering sciences (geology, geography, agrobiology, etc.) by means of manned orbital space laboratories. Relatively detailed discussion is given to the problems of the interpretation of terrain feature pictures from space. Attentively considered are the technique and results of the photometric processing of atmospheric photographs near the horizon with the purpose of studying atmospheric optical non-homogeneities (in particular, aerosol layers). The possible investigations based on the use of data about the outgoing radiation spectra are mentioned. (, , .) . . ( , ) . .  相似文献   

3.
Summary The paper presents a review of the possibilities of using meteorological satellites for investigating various atmospheric phenomena and obtaining data on the physical condition of the atmosphere required for realizing the numerical methods of weather forecast, the synoptical analysis and other purposes. To avoid repetition the review does not include the much important material in the field of satellite meteorology which had been dealt with in earlier reviews.
, , . , .
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4.
nuam aau ¶rt; amu a um ¶rt; ¶rt;a uauu. ¶rt; ¶rt;a, ¶rt;mu auumu m mnam u nu mum ¶rt;a, umam m ¶rt;u z aa n¶rt; uuu, a aau. u¶rt; auum ¶rt;au z naa m mauu ¶rt; amu, naam, m ¶rt;au ¶rt;z naa zauuam u amu ¶rt;.
Summary A formation of ice particles on artificial deposition INis described. INacting in dependence on the temperature and supersaturation over the ice are considered in the 1 D SSconvection cloud model with detailed microphysics including freezing. The limiting influence of the water vapour pressure upon the concentration of active INis shown resulting from the dependence of water vapour pressure on the ice particle concentration.
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5.
Summary The case study presented here is related to the thermodynamic analysis of entrainment and mixing in a shallow cumuls layer. The fair weather situation on 9. 9. 1983, Voves, is characterized by a field of scattered cumuli of the same depths and by a towering isolated cumulus. The clouds were sampled. Two types of analysis were used, the Paluch analysis and saturation point analysis, both of them making use of conserved parameters and a mixing line structure. Both methods gave similar results. For the small cumuli, lateral entrainment prevailed up to the highest penetration level while in the isolated cumulus, cloud top entrainment was the dominant mixing mechanism.
aam nu, nu¶rt; ¶rt;, n m¶rt;uau aau u u uau a. umau n¶rt; 9. 9. 1983 aamum n a a ¶rt;ua mu u aa u ua a. a aa uau nu nu ama. u nu ¶rt;a muna aaua — aau a u aau nu nu m au; u a unm amu naam u n¶rt; mm uu uau. a m¶rt;a ¶rt;au n¶rt; mam. a a na¶rt;a u ¶rt; a nuu, m a uua a ¶rt;uuu au uau aa u u.
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6.
Summary The derivatives of the harmonicsP n (k) (sin O)cos kTO andP n (k) (sin O)sin kTO, occurring in the development of the lunar disturbing potential, are derived upto n=4 and for k== 0, 1, ..., n. The equatorial co-ordinates OTO are referred to the Moon's mass centre; the procedure for the solar disturbing potential is formally identical.  相似文献   

7.
ma n n¶rt;u u¶rt; u, m um u umuu ¶rt; amaa n nu , a¶rt;a n n a m. am nua ¶rt;a aau a¶rt;u n uumaa u ummna a ¶rt;u amuu 1965–1970 . mama u¶rt;, m na an amua ¶rt;mam ¶rt; m, m um n¶rt;um ¶rt;mam mm.  相似文献   

8.
a m m n¶rt; uua ¶rt; au anauu a nmu n¶rt;nuu, m u ¶rt;a a ¶rt;u -um, ma u amu um ¶rt;uam. a namu unm ¶rt;a anau, nu a¶rt;u m m aua n-a. nuam n¶rt; n¶rt;u au — D-nmuamu — naa uu anau ¶rt; n¶rt;u a.  相似文献   

9.
Summary The paper is concerned with the properties of a density distribution within the Earth. A system of density parameter constraints involving Stokes' coefficients of the gravity field and the parameters describing the Earth's figure is derived. A density model, whose parameters fit these constraints, accounts for the fine structure of the gravity field and Earth's figure. Additional condition imposed on the average spherical density model are derived; they guarantee that the average spherical model is compatible with the 3-D density model.
aamuam ma an¶rt;u nmmu mu u. ¶rt;a uma u, auuau au naam nmm ¶rt;u; uma am m naamaumau n u naam nuau u u. mma ¶rt;, naam m ¶rt;mm mu auuau u, nm n¶rt;um uu umnmau m mmaumau n u u u. ¶rt; ma ¶rt;num u, aa¶rt;au a ¶rt; u ¶rt; nmmu, m nuam ¶rt;uu ¶rt; u ¶rt;u m nmm ¶rt;.
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10.
A set of acceleration source spectra is constructed using the observed parameters of the specific barrier model of Papageorgiou and Aki. The spectra show a significant departure from the 2-model at the high frequency range. Specifically, the high frequency spectral amplitudes of seismic excitation are higher as compared to the level predicted by the 2-model. This is also supported by other observational evidence. The high frequency amplitudes of acceleration scale proportionally to the square root of the rupture areaS, to the rupture spreading velocityv, and to the local strain drop (/) (=strain drop in between barriers). The local strain drop in between barriers is not related in a simple way to the global strain drop, which is the strain drop estimated by assuming that it is uniform over the entire rupture area. Consequently, the similarity law does not apply. Using the source spectra which we constructed, we derive expressions for high frequency amplitudes of acceleration such asa rms anda max. Close to the fault both are independent of fault dimensions and scale as (/µ)(f)1/2, while away from the fault plane they scale asW 1/2(/µ)(f)1/2, whereW is the width of the fault and f is the effective bandwidth of the spectra.  相似文献   

11.
Summary The behaviour of the poloidal and toroidal magnetic field at the core-mantle boundary is analysed in more detail, assuming that the conductive layer in the lowest mantle is thin. We can conclude that, in the case of the Z-model of the nearly symmetric hydromagnetic dynamo, the poloidal field may be considered potential everywhere in the mantle and that the azimuthal field depends on the geostrophic azimuthal velocity in the same manner as derived in[1] and[3].
aau ¶rt;-amu n¶rt;nuu m n¶rt; amuu aauum n¶rt;u nu¶rt;a u mu¶rt;a n. am ¶rt;, m Z-¶rt;u nmu umuu¶rt;aum ¶rt;ua aum nu¶rt;a n umam nmua ¶rt; amuu a n¶rt;u . ¶rt;m¶rt;am na [1] u [3] auum auma aum n m auma mu.
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12.
Summary The influence of the velocity of the movement of the centre of the cycloneV c.c. on the rate of amplitudes' change A/t and periods' change T/t of storm microseisms is investigated. The dependence A/t=k V c.c. and T/t=k 1 V c.c. is obtained. Unmovable depression (V c.c. =0) does not stipulate the change of A/t and T/t.
u V c.c. A/t T/t . A/t=k V c.c. T/t=1 V c.c. . (V c.c. =0) A/t T/t.

Presented as a scientific communication to the IASPEI Assembly in Madrid, Sept. 1969.  相似文献   

13.
au u¶rt;um u mu ¶rt; umu u amu, aa aum, u nuu anmuaum n mu , a ma u n¶rt;nu, m amau uu aum mu u( a a) nnua nu u nam nmama aum mu, aa naam uu . au mmuu mu u a auu ¶rt;a aaua a ¶rt;am a mum uumuu naam ¶rt;a na u ama, n¶rt; a¶rt; uu nu aua ¶rt;nuuaum n mu u. mu ¶rt; num uu, a mmmuu namu naamau , ¶rt; m¶rt; u aua nuu anmuaum n, auam mn uu, a m naama .  相似文献   

14.
Summary The relation of short period PKP1 and PKP2 amplitudes from deep earthquakes in the Tonga region observed at a seismological station in Central Europe, is compared with the theoretical relations computed for different source radiation parameters and depths. The Preliminary Earth Model was used in the computations. Qualitatively good agreement of observed and calculated values was found for the radiation pattern corresponding to the likely geometry of the Tonga subduction zone. The influence of the variation of some source and model parameters on the calculated PKP1 and PKP2 relation is discussed.
¶rt;a au mu anum¶rt; mnu¶rt; PKP1 u PKP2 mu mu a, anua ¶rt; u mau ma n, mmmuu mmuuu uuau, aumau ¶rt; a naam ua umua uu aa. ama unaa ¶rt; PREM. a¶rt; u auma uu ¶rt;am am au ¶rt; a uu, mmm mmuu ¶rt;uu a a. ¶rt;am uu auau naam umu u ¶rt;u a uu am mu anum¶rt; PKP1 u PKP2.
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15.
Summary The frequency equation of Rayleigh waves propagating over the free surface of an isotropic, perfectly elastic, heterogeneous semi-infinite medium with material properties varying as = 0 e az , = 0 e az , = 0 e az (a>0) has been obtained. Solution of the frequency equation in closed form is obtained in two cases (i) =0, (ii) =, and the Rayleigh wave dispersion curves for phase and group velocities drawn. In both the cases the medium yields single Rayleigh modes which cannot propagate below certain cut-off frequencies. It is found that in case (i), <c<c 0 and 0.87500 <c g <c 0, and in case (ii), 1.03082 <c<c 1 and 0.90850 <c g <c 1, wherec andc g denote phase nad group velocities respectively, is the constant shear wave velocity of the mediumc 0 andc 1 are the corresponding Rayleigh wave velocities of the homogeneous medium of the same Poisson's ratio. The motion of the surface particles is found to be retrograde elliptical as in the homogeneous case, but the ratic of the major and minor axes now becomes frequency dependent and is plotted against frequency. In both the cases (i) and (ii), the ratio starts at a lower value at the cut-off frequency and approaches the corresponding value of the homogeneous medium at high frequencies.  相似文献   

16.
Summary The effect of the IMF sector boundary crossing (IMF SBC) in the vorticity area index (VAI) — the well-known dip in the VAI after IMF SBC — is found to be independent of the IMF SBC effect in the cosmic ray flux. This finding refutes a recent suggestion by Lundstedt [1] that the IMF SBC effect in VAI is caused by a decrease in cosmic ray flux, but supports the concept of the IMF SBC effects in the ionosphere and atmosphere developed by Latovika [2–4]. Cosmic rays seem to affect the troposphere in another way.
¶rt;mu nu mau nam aum n ( ) a u¶rt; na¶rt;u aumu () — um uu n — a¶rt; auu m ma nm uu . mm mam nam ¶rt;a n¶rt;u ¶rt;m¶rt;a [1], m m a nuu nma uu , n¶rt;¶rt;uam nu m u u am, aum amu [2–4]. am m uu u m um a mn ¶rt;u a.
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17.
Summary The optimization of the method of determining the addition constant of an EDM is discussed. The advantages of the optimization procedure from the point of view of efficiency and improvement of accuracy are reported.
nuuu ¶rt; n¶rt;u a¶rt;¶rt;uu n ¶rt;. u nu n u uu u nu u.
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18.
Summary By using a general model of optimum elimination of systematic effects[5], the procedure has been developed for the optimum processing of gravimetric observations affected by the drift in a one-stage net, and statistically justified characteristics of the accuracy of the points of this net have been determined.
u uuu u ¶rt;u nmua uuauu um amuu uu [5] aamaa m¶rt;ua nmua amuaumuu uu ¶rt; aa ¶rt;-man mu; nu¶rt; mamumuu aamumuu mmu m¶rt; m m mu.
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19.
Summary A comparison has been made between the Townsend primary ionization coefficient, , for dry air and for air with humidities typical of those in the atmosphere. is defined as the number of new electrons produced by an electron per centimeter of drift in a field. A range of field/pressure ratios,E/p 0, of 40 to 100 V (cm torr)–1 was employed. The variation of with humidity is very small.Over the range ofE/p 0 from 50 to 100 V (cm torr)–1, the secondary ionization coefficient, , of a water surface has been found from sparking potential data to be typically 2×10–4. represents the fraction of primary ionizing collisions that ultimately result in the production of additional electrons at the surface.  相似文献   

20.
Summary Based on the relation between the relative sunspot number R, the number of sunspot groups f 0 generated per unit time on the Sun as a whole and their average lifetime T 0 , and on the extrapolation of time behaviour of f 0 and T 0 , it is proved that abnormally high solar activity may be expected in the first half of the 21st century. At this time, the maximum annual relative sunspot numbers RM of the 11-year cycles should reach values of about 300 units. This abnormally high solar activity in the next century can be understood as the antipole of the Maunderean minimum. This forecast is used to discuss some of the possible consequences of this abnormally high solar activity for the processes on the Earth: changes of climate (heat waves and draughts in Central Europe), in the higher layers of the Earth's atmosphere (anomalous propagation of radio waves, increased effect of the density of the upper atmosphere on the orbits of man-made satellites), in seismicity (increased seismic activity in Europe and Southeast Asia), for technical devices (induced electric currents), in the biosphere. etc.
a mu ¶rt; uau a R nm, unn nm f 0 uu ¶rt;uu u a ë u u ¶rt; n¶rt;ummu uu 0 , u a manuu ¶rt;a f 0 u 0 , naa, m n nu ¶rt; 21 a u¶rt;am uum amum. aua¶rt;u ua a R m¶rt; 11-mu ua m u ¶rt;muam au 300 ¶rt;uu. m uum amum ¶rt; nuam a amun¶rt; a¶rt; uua. a m na ¶rt;am m n¶rt;mu m uum amumu a n nmau a : a uu uama (aa u a n¶rt;a ¶rt; n), a u u am u (aa anmau a¶rt;u, uu n nmmu u am a ¶rt;uu um m), a um (na ua amum n u -m uu), a muu mma (u¶rt;ua muu mu), a u u ma ¶rt;a.
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