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Summary In the introductory part of the paper, a method of computing spectra by computer is described, which cuts down the computer time required without using the Fast Fourier Transformation. Windows which can be used to adjust the resultant spectrum are described. The spectra of a constant, a linear function, a sine function, of the superposition of two sine functions and of the superposition of a sine function with a constant and linear function are described in detail and it is demonstrated how these spectra change when different types of windows are used. The suitability of the separate windows for various purposes is discussed. Finally, in the case of the superposition of two sine oscillations it is shown under what conditions the two frequency components can be distinguished. 相似文献
54.
Jaroslav Kubík Reviewer A. Janáčková Reviewer V. Červený 《Studia Geophysica et Geodaetica》1988,32(3):287-299
Summary The dependence between Pn-wave velocities and the surface heat flow, temperature at the core-mantl boundary and thickness of the Earth's crust for continents (Europe, Asia, North America and Australia) was investigated statistically in connection with the problem of lateral inhomogeneities in the upper mantle. The relations obtained were compared with those determined under laboratory conditions. The conclusion is that temperature and pressure effects may provide additional explanations of the regional variations of Pn-wave velocities observed in most continents.
auum ¶rt;auu mu n¶rt; a nmu uua(Pn ), nm mn nm, mnam a u m mum a u¶rt;aa u n uuuma ¶rt;¶rt;m mu Pn. nua ¶rt;a mama aam u¶rt;au nu m n¶rt; amuu u u ¶rt;au u mnam a¶rt;um mmmuu mamau n¶rt;aa am. am ¶rt;, m ua uu m Pn- ¶rt; amu muma n¶rt;m auu m¶rt;uauu u a nmu muua.相似文献
55.
Vladimír Tobyáš Jaroslav Fiedler Dana Knaislová Dana Procházková Reviewer I. Pšenčík 《Studia Geophysica et Geodaetica》1985,29(1):68-74
Summary The effectiveness of recording seismic phenomena in the Kruné hory (Mts.) region in NW Bohemia by selected stations in the CSR, GDR and Poland has been estimated. Magnitude isolines of the weakest earthquakes, which can be localized and detected with an 0.9 probability, were calculated on the basis of the level of seismic disturbances at the individual stations and of the empirical dependence of the attenuation of seismic waves with distance.
a a mum umauu uu u amu ¶rt; ana¶rt; uu uau mauu a mumuu , u a a uu n a m¶rt; mau u nuu auumu amau uu m amu u auma uuuu aum¶rt; a a mu, m mm 0.9 auuam u aum.相似文献
56.
nma nu SS u nmau u nau a¶rt;a ¶rt;u nma u u a au 11-mu ua. u ¶rt; nm ¶rt; n. a¶rt;am nuu nu SS u. 相似文献
57.
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
58.
Jaroslav Hofierka Juraj Parajka Helena Mitasova & Lubos Mitas 《Transactions in GIS》2002,6(2):135-150
Regularized Spline with Tension (RST) is an accurate, flexible and efficient method for multivariate interpolation of scattered data. This study evaluates its capabilities to interpolate daily and annual mean precipitation in regions with complex terrain. Tension, smoothing and anisotropy parameters are optimized using the cross-validation technique. In addition, smoothing and rescaling of the third variable (elevation) is used to minimize the predictive error. The approach is applied to data sets from Switzerland and Slovakia and interpolation accuracy is compared to the results obtained by several other methods, expert-drawn maps and measured runoff. The results demonstrate that RST performs as well or better than the methods tested in the literature. The incorporation of terrain improves the spatial model of precipitation in terms of its predictive error, spatial pattern and water balance. 相似文献
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60.
Gunther Kletetschka Petr Pruner Daniela Venhodova Jaroslav Kadlec 《Geochemical transactions》2007,8(1):2
A magnetic signature of tree rings was tested as a potential paleo-climatic indicator. We examined wood from sequoia tree,
located in Mountain Home State Forest, California, whose tree ring record spans over the period 600 – 1700 A.D. We measured
low and high-field magnetic susceptibility, the natural remanent magnetization (NRM), saturation isothermal remanent magnetization
(SIRM), and stability against thermal and alternating field (AF) demagnetization. Magnetic investigation of the 200 mm long
sequoia material suggests that magnetic efficiency of natural remanence may be a sensitive paleoclimate indicator because
it is substantially higher (in average >1%) during the Medieval Warm Epoch (700–1300 A.D.) than during the Little Ice Age
(1300–1850 A.D.) where it is <1%. Diamagnetic behavior has been noted to be prevalent in regions with higher tree ring density.
The mineralogical nature of the remanence carrier was not directly detected but maghemite is suggested due to low coercivity
and absence of Verwey transition. Tree ring density, along with the wood's magnetic remanence efficiency, records the Little
Ice Age (LIA) well documented in Europe. Such a record suggests that the European LIA was a global phenomenon. Magnetic analysis
of the thermal stability reveals the blocking temperatures near 200 degree C. This phenomenon suggests that the remanent component
in this tree may be thermal in origin and was controlled by local thermal condition. 相似文献