首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 93 毫秒
1.
auuau uu muna a f>1,5 , aumua ¶rt; a nmua uu m u a ¶rt; a mau. mu a aum nm uu, umu a mauu aa (L=2,1) n¶rt; nm uu (L=5). m mmmum mu umua uu, umu a mu mau. au uu a nm m, m a um nmam a 2000–3000 u anu u a L=2,2–5,9. au mmmu nma aamumu a u nmu uu a¶rt;am u amu aua uu a L 3,5. aa, m a mauu aa u ¶rt;a a¶rt; nuu uu a , umum uuu n¶rt; a¶rt;a a nmu. au a n¶rt;num, m am a L 3,5,¶rt; aam au uu u au mmu nma aamumu a u nmu uu, aa ¶rt;amua anau a nana. m u m amu mm au anum u ¶rt; ¶rt;a ua n¶rt;u anmau u ¶rt; — ua.  相似文献   

2.
Using the periodicities obtained by a Maximum Entropy Spectral Analysis (MESA) of the Arosa total ozone data (CC) series for 1932–1971, the values predicted for 1972 onwards were compared with the observed values of the (AD) series. A change of level was noticed, with the observed (AD) values lower by about 7 D.U. Also, the matching was poor in 1980, 1981, 1982. In the monthly values, the most prominent periodicity was the annual wave, comprising some 80% variance. In the 12 month running averages, the annual wave was eliminated and the most prominent periodicity wasT=3.7 years, encompassing roundly 20% variance. This and other periodicities atT=4.7, 5.4, 6.2, 10 and 16 years were all statistically significant at a 3.5a priori i.e., 2a posteriori level. However, the predictions from these were unsatisfactory, probably because some of these periodicities may betransient i.e., changing amplitudes and/or phases with time. Thus, no meaningful prediction seem possible for Arosa total ozone.  相似文献   

3.
Summary The geopotential scale factor R 0 =GM/W 0 has been determined on the basis of satellite altimetry as R 0=(6 363 672·5±0·3) m and/or the geopotential value on the geoid W 0 =(62 636 256·5±3) m 2 s –2 . It has been stated that R 0 and/or W 0 is independent of the tidal distortion of surface W=W 0 due to the zero frequency tide.
¶rt;a nmu amumuu u ama amnmuaa R 0 =GM/W 0 =(6 363 672,5±0,3) m u/uu aunmuaa a nmuu¶rt;a W 0 =(62 636 256,5±3) m2 s–2. m, m R 0 u/uu W 0 auum m nm amu a a nuu ¶rt;au nmu W=W 0 .
  相似文献   

4.
Moment tensors of ten witwatersrand mine tremors   总被引：1，自引：0，他引：1  
Ground motions, recorded both underground and on the surface in two of the South African Gold mining districts, were inverted to determine complete moment tensors for 10 mining-induced tremors in the magnitude range 1.9 to 3.3. The resulting moment tensors fall into two separate categories. Seven of the events involve substantial coseismic volumetric reduction-V together with normal faulting entailing shear deformation AD, where the summation is over fault planes of areaA and average slipD. For these events the ratio-V/AD ranges from 0.58 to 0.92, with an average value of 0.71. For the remaining three events V is not significantly different from zero; these events are largely double-couple sources involving normal faulting. Surprisingly, the two types of source mechanism appear to be very distinct in that there is not a continuous distribution of the source mix from V=0 to-VAD. Presumably, the coseismic closure indicates substantial interaction between a mine stope and adjacent shear failure in the surrounding rock, under the influence of an ambient stress for which the maximum principal stress is oriented vertically.  相似文献   

5.
Summary The distribution of radioactive(Th, U, K), major and selected trace(Rb, Sr, Ba, Y, Zr, V, Cr, Ni) elements of granulites from the Saxonian Granulite Complex was studied. Similarly to the South Bohemian granulites, the Saxonian granulites can be divided according to the contents of their major and trace elements into two main groups, groupA containing mostly acid and subacid granulites (K 2 O>2.5%, SiO 2 >68%), and groupB containing mostly intermediate and basic granulites (K 2 O<2.5%, SiO 2 <68%). Statistically significant differences between groupsA andB were found for all major oxides and several trace elements(Rb, V, Cr, Ni). The Saxonian granulites follow the same calc-alkaline trend as the South Bohemian, granulitesA being placed mostly in the rhyolite field and granulitesB mostly in the dacite, andesite and basalt fields of this trend. The investigated granulites are characterized by a considerable scatter ofTh andU contents accompanied by very variableTh/U ratios; theTh andU concentrations of granulitesA are substantially lower than is usual for rocks of corresponding acidity.
¶rt;a an¶rt;u a¶rt;uamu(Th, U, K) u ua ¶rt;u(Rb, Sr, Ba, Y, Zr, V, Cr, Ni) m aum n¶rt;a aaum na. naa, m u¶rt;aum n uu aam n aaum u ¶rt;u am aua, u u uu. aum n u uu ma a¶rt;um ¶rt; ¶rt;nn; nnA nua¶rt;ama a au¶rt; u au¶rt;aum (K 2 O>2,5%, Si O 2 >68%), nnB ¶rt;u u aum (K 2 O<2,5%, SiO 2 <68%). ¶rt; muunnau mm mamumuu m au ¶rt; a u u ¶rt; m ¶rt;u m(Rb, V, Cr, Ni). auaum n¶rt;¶rt;m um- m¶rt; a u -uaum;aumA a¶rt;ma a uum n, uaumB a a ¶rt;aum, a¶rt;um u aam n m m¶rt;a. ¶rt;aum — u unnA — aamum uu ¶rt;au da¶rt;uamu mTh uU.
  相似文献   

6.
By applying the perturbation theory to theXYZ algorithm (a kind of variational method), the difference f in free vibration frequencies between sphere and ellipsoid was approximated as , where i and i (i = x,y andz) (i=x, y andz) are aspherical coefficients and asphericities of the ellipsoid, respectively. We developed an analytic method to compute the aspherical coefficients719-4 by using theXYZ algorithm. A numerical example was given for an ellipsoidal olivine, and an attempt was made to estimate the asphericities of the specimen by a least-squares method, based on the relationship between frequency shift and asphericity.  相似文献   

7.
We estimate (/T) P of the lower mantle at seismic frequencies using two distinct approaches by combining ambient laboratory measurements on lower mantle minerals with seismic data. In the first approach, an upper bound is estimated for |(/T) P | by comparing the shear modulus () profile of PREM with laboratory room-temperature data of extrapolated to high pressures. The second approach employs a seismic tomography constraint ( lnV S / lnV P ) P =1.8–2, which directly relates (/T) P with (K S /T) P . An average (K S /T) P can be obtained by comparing the well-established room-temperature compression data for lower mantle minerals with theK S profile of PREM along several possible adiabats. Both (K S /T) and (/T) depend on silicon content [or (Mg+Fe)/Sil of the model. For various compositions, the two approaches predict rather distinct (/T) P vs. (K S /T) P curves, which intersect at a composition similar to pyrolite with (/T) P =–0.02 to –0.035 and (K S /T) P =–0.015 to –0.020 GPa/K. The pure perovskite model, on the other hand, yields grossly inconsistent results using the two approaches. We conclude that both vertical and lateral variations in seismic velocities are consistent with variation due to pressure, temperature, and phase transformations of a uniform composition. Additional physical properties of a pyrolite lower mantle are further predicted. Lateral temperature variations are predicted to be about 100–250 K, and the ratio of ( lnp/ lnV S ) P around 0.13 and 0.26. All of these parameters increase slightly with depth if the ratio of ( lnV S / lnV P ) P remains constant throughout the lower mantle. These predicted values are in excellent agreement with geodynamic analyses, in which the ratios ( ln / lnV S ) P and ( / lnV S ) P are free parameters arbitrarily adjusted to fit the tomography and geoid data.  相似文献   

8.
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   

9.
Marked wavelike variations of the lower stratospheric wind observed on 7–10 May, 1985 by an MST radar in Japan (by the MU radar) are analyzed assuming that they are induced by monochromatic internal inertio-gravity waves. These variations are mainly composed of two modes (periods: 22 and 24 hours), both of which have zonal phase velocities (C X ) slower than the mean westerly wind (). A statistical analysis of the zonal phase velocity shows thatC X above andC X below the tropopause jet stream, which is considered to be a vivid proof of wave selection due to the tropospheric mean flow and upward wave emission from the tropopause jet. A comparison between the MU radar results and routine meteorological observations leads to the conclusion that the marked waves appear when the jet stream takes a maximum wind speed.  相似文献   

10.
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.
  相似文献   

11.
Summary A forecast model to predict the fluctuations of level AT 500 hPa in a selected grid of points is derived. The solution of the compensation equation is sought in the form of a trigonometric polynomial in three idependent variables. It constitutes the basis of a numerical solution of the prediction problem with the use of a high-speed computer. A three-month forecast of the altitude fluctuation of level 500 hPa is evaluated by means of the daily values of the correlation coefficient. The results are satisfactory and the general evaluation shows the model to be prospective.
¶rt;um nmua ¶rt; ¶rt; na au m AT 500a a uum m m. u au nauu um u¶rt; mu mu nua m m auu n. m u u nmu a¶rt;au a . u¶rt;um a m na au m 500a nu nu m au uuma uu. mam m anumu, u nu ¶rt; n¶rt;mam nnmu.
List of symbols used * coupling coefficient between two conjugate atmospheric elements - * ageostrophicity coefficient of the atmospheric system - Coriolis' parameter (=2 sin) - , * geographic latitude, geographic longitude - *, geopotential reference and pressure levels - , * compensation and coupling frequencies - integration field over the entire atmospheric system - A** constant (A*=2 2(*+*)) - A r ,B r ,C r ,D r constants related to subsystem -r- - A s ,B s ,C s ,D s constants related to subsystem -s- - B** constant (B**= 4(*2+2**)) - C r constant (i=1, 2, 3, 4) - E k ,E v ,E p energies of the atmospheric system: kinetic, internal and potential - K transformation constant - m total number of generalized frequencies - R(T) frequency characteristics of the numerical band filter - r0(t),r1(t) daily values of the correlation coefficient - Q heat - x, y coordinates in the reference plane - t time - p 2 Laplace's differential operator in thep-system  相似文献   

12.
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   

13.
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.
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.
  相似文献   

14.
Summary The accuracy of wave field extrapolation is studied with respect to the discretization of field data and integral extrapolator. Assuming a far-field approximation of the Rayleigh-Sommerfeld solution for a two-dimensional scalar wave equation, the minimum and the maximum transmitted frequency are expressed as functions of the sampling intervals t, x, and the half-width x0 and angle a of the migration aperture. The theoretical limitation of the transmitted frequency band is tested on numerical examples.
aamuam mm manuu auumu m ¶rt;umuauu n u uma manu nama. ¶rt; u uma u -¶rt;a ¶rt; ¶rt; a au, ¶rt; nuuuu ¶rt;a n mu ¶rt; uua u aua n¶rt;aa amm a uu m a -nmam ¶rt;umuauu t u , nuu 0 u a a uau anm. mu n¶rt;u amm ¶rt;uanaa mmua a u nua.
  相似文献   

15.
Summary Spatial and temporal variability of natural ELF-VLF phenomena field intensity has been studied using data from Interkosmos satellites with apogees below 2000 km. The results show a distinct dependence of the diurnal variation and latitudinal intensity distribution on the magnetic activity. The L-value at which the maximum of plasmaspheric noise occurs, e.g., correlates better with the Dst-index than with other indicies.
mama u a auau anmu n mm - u a ua a uu ¶rt;a uu m an u 2000 . mam naam m auum m ¶rt;a u um an¶rt;u uu m aum amumu. uua L-naama, a m nm au naa uu, um Dst-u¶rt; ¶rt;uu u¶rt;auaum amumu.
  相似文献   

16.
Summary Problems of occurrence of density inhomogeneities in the upper mantle are discussed and their gravitational effects in the region of Central Europe are investigated. Attention is namely devoted to the density contrast between the asthenosphere and the lower lithosphere, and its possible dependence on depth.
¶rt;am n nu nmm ¶rt;¶rt;m amuu u uaumau ¶rt;mu a mumuu ¶rt; n. uau ¶rt;m n¶rt; nmm mam ¶rt; am u um u auumu mu aau.
  相似文献   

17.
Summary The relation between geomagnetic activity and solar activity is studied in long intervals and in individual 11-year cycles, characterized by certain basic parameters, in connection with investigating the prognostic significance of long-term fluctuations of geomagnetic activity [1, 2]. A number of properties as well as sufficiently close relations with a prognostic significance have been found, such as the secular variation of geomagnetic activity, the 22-year cycle of change in the form of the behaviour of geomagnetic activity in 11-year cycles, long-term concurrence of solar and geomagnetic activity and its changes within the 11-year cycle, relations between solar and geomagnetic parameters characterizing the 11-year cycle.
a auu uu u ¶rt; uaum amum ¶rt;u nma u u m¶rt; 11-mu ua am mu ¶rt; ¶rt;m nuauaum amumu.
  相似文献   

18.
Summary Dispersion in Rayleigh waves is discussed for semi-infinite media with = 1(1 ± cos s z) and = 1(1 ± cosh s z), being the rigidity of the medium. A few workers tried with the above Fourier type of model but failed to find the dispersive nature. Because they neglected s due to the complexity of the calculation they arrived at a non dispersive frequency equation. This difficulty is removed in this paper and a dispersive frequency equation is obtained which shows both direct and inverse dispersion. The second model leads to non-convergent solution forz but shows many interesting results which are also discussed.  相似文献   

19.
u¶rt;m mam uu u nu a¶rt;u m¶rt;3 (a na¶rt;u) a amm 1539 a amuu aa a nu¶rt; am 1978 — am 1981. u m nuau nu mma. a¶rt;am u¶rt;aa ma (a aumu) u a auau nu, u u aauu u an u u. numa u am au nu ¶rt; =60° na¶rt;am. au naa, m nu u um a a ¶rt;a ¶rt;m a nu¶rt;, nu a m n u nua nu mma am 1980.  相似文献   

20.
Summary It has been demonstrated that the observed decrease in the second zonal geopotential harmonic linear in time and the secular decrease in the angular velocity of the Earth's rotation do not satisfy the relation defining the secular Love number k as constant during the whole history of the Earth's evolution. The discrepancy disappears if it is assumed thatdk/dt=–2.4×10–6 cy–1 .
aa, m a ¶rt;a au m aauunmuaa u u a ¶rt;a u mu au u ¶rt;mm mu, n¶rt; u a a nm mu umuu u. a uam, u ¶rt;nmumdk/dt=–2,4·10 –6 (mmu)–1 .
  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号