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1.
Summary Echo soundings of the U.S. Cruiser Milwaukee in the Puerto Rico Trough in 1939 are briefly discussed, and two depths of 30246 feet or 9219 m, found at 19° 36 N, 68° 20.5 W and at 19° 35N, 68° 8.75W, are stated to be the greatest depths which are known so far in the Atlantic Ocean.  相似文献   

2.
Summary The paper is concerned with the mathematical properties of the density distribution within the Earth obtained by inverting of the external gravity field, provided an Earth's reference density model, used as the initial guess, is available. The method of regularization, which proves the existence, the uniqueness and the stability of the solution, which is nearest the initial guess in the L 2 norm, is described.
nua m¶rt; uauu ¶rt;am a¶rt;au ¶rt; aumau n u uma, m uma aaa a an¶rt;u nmmu . mm m¶rt; n¶rt;maum m amu u, m ¶rt;a, mu u uu aa u.
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3.
Résumé A partir de sismogrammes enregistrés dans deux stations sismologiques longues périodes identiques (WWSSS) installées à Machhad (36°1840N, 59°3516E) et à Chiraz (29°3040N, 52°3134E), la vitesse de phase des ondes de Rayleigh a été calculée dans cette région. D'après les résultats obtenus par l'étude des ondes de volume dans cette même région des modèles ont été établis. Le modèle s'accordant le mieux avec les résultats expérimentaux a une croûte d'environ 50 km d'épaisseur et comporte une couche à faible vitesse située entre 100 et 200–250 km de profondeur.  相似文献   

4.
The Narmada-Son lineament (NSL) forms a major tectonic feature on the Indian subcontinent. The importance of this lineament lies in its evolution as well as its tectonic history. The lineament seems to have been active since Precambrian times. In order to understand the history of its evolution, it is necessary to know what igenous activity has been taking place along this lineament, and how the Deccan trap volcanics, which cover large areas along this lineament, have erupted.For the study of this problem an analysis of the aeromagnetic anomaly map lying between 76°15 to 77°30E and 21°45 to 22°50N has been carried out. Four different profiles (B 1 B 1,B 2 B 2,B 3 B 3 andB 4 B 4) have been drawn in N-S direction over this area and interpreted in terms of the intrusive bodies present within or below the surface of Deccan trap exposures. Inversion and forward modelling techniques have been adopted for interpretation purposes. An analysis of frequency spectra along the profiles has also been carried out to estimate the average depth of the different magnetic bodies. These results have been correlated with the available geological information. It has been found that most of the small wavelength anomalies are caused by dyke-like bodies within or below the Deccan trap at a depth of less than 0.5 km.  相似文献   

5.
Summary Utilising two years data collected at two tropical coastal stations, Madras (13°04N, 80°15E) and Waltair (17°42N, 83°18E) and for one tropical continental station, Nagpur (21°09N, 79°07E), the authors have re-evaluated the constants ofBrunt's regression equation. Analyses of the observations for Waltair and Nagpur show good correlation coefficients (r) between the values of the effective emissivity of the atmosphere (the effective emissivity is the ratio of incoming long-wave sky radiation at the surfaceR s , to black body radiation T 4) and the square root values of surface vapour pressuree (mb). The value ofr for Waltair from radiometer observations is 0.98. It is also determined for Waltair and Nagpur from Ångström compensation pyrgeometer observations as 0.83 and 0.91 respectively. A low correlation co-efficient 0.56 is obtained for Madras. It might be due to higher surface vapour pressure values at Madras than at Waltair and Nagpur. The applicability of the reduced regression equations are examined for different years for the different stations. The agreement between the computed values with the new regression equations and the observed long-wave sky radiation at the surface seems to be quite good.  相似文献   

6.
¶rt;am aum ua mm, m um aua m uuu u u amu n¶rt;u. aamuam m unau au au ma ¶rt; u nmm ¶rt; u. ¶rt;a u auu m uuu ¶rt;a, amuu u   相似文献   

7.
The rocketsonde data obtained from the launchings made at Thumba (8°3215N, 76°5148E) during the winter period 1970–71, as already reported, have indicated that warmings of noticeable magnitude occurred at high levels (upper stratosphere and mesosphere) over this tropical station during the period mentioned. The mean monthly radiosonde temperatures of 50, 100 and 300 mb levels at Thumba (Trivandrum) and Delhi (28°35N, 77°12E) during the same period have also pointed out certain anomalies consistent with the warmings referred to above at Thumba. The radiosonde temperatures of the two stations, Thumba (Trivandrum) and Delhi, have now been examined, along with the values of total ozone, for the ten winter periods commencing from 1961–1962. The analysis has pointed out the possibility of high-level warmings also having occurred in the past over the Indian region during the winters of 1963–1964 and 1967–1968, which are also the periods when prominent warmings are definitely known to have occurred at higher latitudes. The behaviour of total ozone has been found to be different in the different years of the warmings. The features noticed have been presented and discussed.  相似文献   

8.
Rocket-borne ultraviolet photometers operating at =0.31 m have been used at Thumba (8°33N, 76°52E) to make measurements of atmospheric scattering at tropospheric and lower stratospheric altitudes. Measurements could be made of the amplitude of the scattered fluxes and the angular distribution up to an altitude of about 24 km on three rocket flights conducted as part of the 16 February 1980 solar eclipse campaign. These measurements have been used to study the size distribution as well as the number densities of aerosols in the troposphere and lower stratosphere over Thumba.  相似文献   

9.
a mam 10-mu u¶rt;au ¶rt;uauu nmu a anam. auum aam mua ¶rt;uu u nu amu uu, a , muu, u auauu n u mmu u uu umaa u ¶rt; nmu uuau.  相似文献   

10.
Summary Simple linear representation of the components of an approximate plane solution of point mass loading of the Earth's surface in a conveniently chosen coordinate system leads to selection of a 2nd-degree curve which is the best fit of the spherical solution for the given Earth model. The new approximate solution, which, analogously to the plane solution, can be called a parabolic solution, enables the simple input parameters of the plane solution to be used also for substantially larger angular distances. The comparison with the spherical solution is carried out by computing the effects of the M2-wave of ocean tides. The results of the computations for the tidal station Brussels prove the two solutions to be in sufficient agreement for global problems as well.
m nu uau aa nuuum nm u m m au nmu u n¶rt;¶rt; um ¶rt;uam ¶rt;m ma u m mnu, ma auu a n¶rt;¶rt;um u u ¶rt; ¶rt;a ¶rt;u u. nuuum u, m n aauu nm u aam naauu u, nm unam nm ¶rt; ¶rt;a nm u ¶rt;a ¶rt; m u amu. au uu u m uu uu 2 u nuu. mam uu ¶rt; nuu mauu ¶rt;aam ¶rt;mum au u u ¶rt;a ¶rt;a a¶rt;a.
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11.
Summary Magnetic variations were recorded along three profiles crossing the southeastern margin of the Bohemian Massif. The data were processed in order to get induction vectors (Wiesevectors) and in-phase and out-of-phase induction vectors (Schmucker-vectors). Several events of field variations were separated into external and internal parts. The same events were also treated by a physical-statistical approach. Taking into account these results, we were able to delineate a zone of electrical inhomogeneity. It is in close relation to the Moravo-Silesian lineament. The depth of the internal anomalous field source was estimated at 20 to 25 km.
¶rt;a u uuau n uu n nu, nu — u. u¶rt;uu ( u), n u u n¶rt; u n u¶rt;uu ( ), n ¶rt;u n uau u u u n au ¶rt; uu-uuu ¶rt; u ¶rt;¶rt;u na¶rt; nu -uu . ¶rt; au uu a n a u n¶rt; 20–25 .
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12.
Riassunto Per rappresentare una curva spaziale su un piano si può piegare un filo metallico secondo la curva e fotografarlo, operazione che però richiede molto tempo. Nel presente articolo l'A. illustra un dispositivo ottico che, sostituito alla matita della tavola di egresso della macchina diBush, è atto a descrivere su pellicola una curva simile all'immagine fotografica del filo. In questo studio si sono considerati soltanto i casi in cui la sorgente di luce che illumina la è all'infinito o nella origine delle coordinate, mentre il punto di vista à sempre all'infinito.
Summary One may represent a spatial curve on a plane by bending a metal thread along the curve and then photographing it, but in this way much time is wasted. In the present paper the A. suggests an optical device which, replaced to the pencil of the out-put table ofBush's machine, traces on film a curve that should look like the photographic image of the thread. In this study were taken into account only the cases in which the light source lighting , is at the infinite or in the coordinate origin, while the point of view is always at the infinite.
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13.
Summary The measuring systems of Askania gravity meters are assumed to have 3 degrees of freedom. The axis of rotation of the beam can also be displaced in the vertical and horizontal directions. The equations of equilibrium of this system (25)–(27) were used to derive the expressions for the effect of displacing the calibration ball, for the scale equation and for the sensitivity of the gravity meter. Equations (33), (34) and (39) refer to gravity meters with a photoelectric transducer, and Eqs (46), (47) and (49) to gravity meters with a capacitive transducer.
uum umaum au n¶rt;naam 3 mnu ¶rt;. au aa m m nam mua uuma anau. au au m um (25)–(27) ¶rt; au ¶rt; ¶rt;mu nu au aua, ¶rt; aua a u ¶rt; mummuauma. aum mmuu mm m au (33), (34), (39), ¶rt;aum m mm au (46), (47), (49).
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14.
Summary Teleseismic P residuals calculated for waves arriving from various azimuths and angles of incidence, and a 3-D inversion of the residuals provided the basis for characterizing the uppermost mantle structure beneath Bulgaria. The Moesian Platform and the Rhodopean Massif are two different blocks characterized by a lithosphere thickness of about 130–140 km with a zone of lithosphere thinning along their contact. Both units have opposite patterns of the directional dependence of relatively high and low P velocities. This directional dependence is interpreted by dipping anisotropic structures in the subcrustal lithosphere, which probably represent remnants of paleosubductions of an old oceanic lithosphere.
auma u nu¶rt;u n¶rt; au aumau u au. a uu mu ¶rt;am ¶rt; aamuauu mm amuu n¶rt; au. uua nama u ¶rt;nu au, ¶rt;a au a mu um nuuum 130–140 ¶rt; uma m ¶rt; u mama. a a aamua nmun ana auum mum u u mu . ma anaa auum umnmuaa a nu aumn mm amu. mu mm n¶rt;maum a mamu na¶rt;u ma au um.
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15.
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.
¶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.
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16.
Summary A preliminary observation has been made of the magnetic fabric in 14 specimens of undeformed sediment which exhibit repeatable principal orientation in undemagnetized state as well as after some steps of thermal demagnetization. They were chosen from 2000 specimens of the Tertiary formations of inland fluvio-lacustrine facies in the Qaidam basin, NW China. It was found that no large changes in magnetic fabric occur after stepwise thermal demagnetization up to 300°C, but some significant changes take place after treatment at higher temperature (500° up to 750°C). It is shown that the orientations of the 3 principal axes remain unchanged after each demagnetization step, whereas the differences between the principal values (L=K1–K2 and F=K2–K3) are greatly enhanced after high temperatures have been applied. The enhancement of L and F with no change in principal orientations facilitates the determination of the principal orientations. In our case one may easily measure the thermally enhanced magnetic lineation to estimate the palaeocurrent direction.Presented at 2nd conference on New Trends in Geomagnetism, Bechyn Castle, Czechoslovakia, September 24–29, 1990.  相似文献   

17.
Summary The paleomagnetism of twenty six oriented samples of red sandstones from three different sites located in Satyavedu hills (near 13°30N, 79°55E) and belonging to coastal upper Gondwana formations of India has been studied. These sandstones have been considered to be equivalent of Tirupati sandstones of Lower to Middle Cretaceous age from Godavari valley on stratigraphic considerations. Consistent directions of magnetization were obtained from two different sites after stability tests. Results from one site gave ancient pole position at 26°N, 67°W, very close to that obtained for Tirupati sandstones, thus confirming the geologic correlation. Results from the second site were rejected on account of instability and those from the third site gave pole position at 79°48N, 76°58W. This site appears to have been remagnetized during Pleistocene times when there was large deposition of laterite in the area. Study of magnetic properties of these sandstones revealed that the magnetization was of the nature of CRM and the NRM was carried almost entirely by red coating on silica grains.N.G.R.I. Contribution No. 70-169.  相似文献   

18.
Summary The vertical distribution of the contribution of the energy flux density due to the Alfvén(ordinary) wave, guided by the geomagnetic field(and propagating through the ionosphere to the Earth's surface) in the horizontal direction is demonstrated in the mechanism of the horizontal propagation of the Pc1 signal. The distribution with height is shown of the variations of the polarization characteristics of the propagating wave(e.g. the rotation of the polarization plane, changes in ellipticity, attenuation, etc.), which are the result of coupling in the denser layers of the low ionosphere in which also suitable isotropic(extraordinary) modes are generated. The results obtained using the method described in[4, 13] are demonstrated on a model of the daytime ionosphere under incidence of ordinaryL-modes, frequency f=0.3 Hz, and various meridional angles at the ionosphere.
auauma anmau uaa Pc1 naa m an¶rt;u ¶rt;u nmmu ma uu uma anauu maum n n¶rt; , anma u nmu. naa m an¶rt;u uu aamumu nuauu anma (nauau nmu nuauu, uu unmumu, amau u m.¶rt;.), m m ¶rt;mu au¶rt;mu na uu u . ¶rt; mum n¶rt;¶rt;u umn() ¶rt;. mam num m¶rt; [4, 13] ¶rt;mua ¶rt;u ¶rt; u nu na¶rt;uu a u L-¶rt; amm f=0,3 n¶rt; au u¶rt;uau au.
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19.
Summary In this paper an attempt is made to define the time variations of theD-region main aeronomical parameters under non-equilibrium conditions by using experimental data by the A3 method, phase-height method and satellite data for the short-wave X-radiation. The SID effect of day-time and time variations of 21 August 1969 electron concentrationN(t) and recombination coefficient (t) are investigated. It is shown that during SID effect (t) increases.
Résumé Dans le présent travail on a procédé à une expérience pour déterminer les variations temporelles des principaux paramètres aéronomiques en utilisant des données expérimentales par la méthode A3 de mesure de l'absorption ionosphérique, la méthode phase-altitude et des données satellites aux rayons X durs. On a examiné les variations diurnes et les variations temporelles lors de SID effet durant le 21 Août 1969, de la densité électroniqueN(t) et du coefficient de récombinaison (t). On a montré que lors de SID effet (t) s'accroît.
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20.
Swept-frequency (1/10 MHz) ionosonde measurements were made at Helston, Cornwall (50°06N, 5°18W) during the total solar eclipse on August 11, 1999. Soundings were made every three minutes. We present a method for estimating the percentage of the ionising solar radiation which remains unobscured at any time during the eclipse by comparing the variation of the ionospheric E-layer with the behaviour of the layer during a control day. Application to the ionosonde date for 11 August, 1999, shows that the flux of solar ionising radiation fell to a minimum of 25±2% of the value before and after the eclipse. For comparison, the same technique was also applied to measurements made during the total solar eclipse of 9 July, 1945, at Sörmjöle (63°68N, 20°20E) and yielded a corresponding minimum of 16 ± 2%. Therefore the method can detect variations in the fraction of solar emissions that originate from the unobscured corona and chromosphere. We discuss the differences between these two eclipses in terms of the nature of the eclipse, short-term fluctuations, the sunspot cycle and the recently-discovered long-term change in the coronal magnetic field.  相似文献   

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