Autocovariance function and the spectral density of the anomalous gravitational field,transformed by an integral operator of the convolution type     

Ludmila Kubáčková  Reviewer M. Burda 《Studia Geophysica et Geodaetica》1974,18(4):329-338

Summary The transfer of the fundamental statistical characteristics, i.e. covariance function and the density of the statistical power spectrum, of a random homogeneous field across a linear homogeneous filter is investigated. The results obtained are applied to the study of the said statistical characteristics of transformed anomalous gravitational field.  相似文献   

Change in the spectrum of a gravity anomaly caused by expressing it discretely     

Ludmila Kubáčková  Reviewer M. Burda 《Studia Geophysica et Geodaetica》1973,17(4):306-313

Summary The spectral content of an operation which may be called the operation of selecting the step for treating a certain, discretely expressed datum, continuous by nature is shown.  相似文献   

On the problem of the existence and uniqueness of a discrete,surface, optimum wiener filter,applied to the filtering of geophysical fields     

Ludmila Kubáčková  Reviewer O. Šefl 《Studia Geophysica et Geodaetica》1973,17(3):199-204

Summary Proof is given of the existence and uniqueness of a discrete, surface, optimum (in the Wiener sense) filter for filtering geophysical fields considering a spectral approach to the construction of the said filter. It is also shown that the filtration coefficients and the filtration errors of the filter, constructed with the help of statistical estimates of the required spectral densities, converge towards their theoretical values. From the mathematical point of view, this paper concludes the building-up of the mathematical model of the discrete Wiener optimum surface filtration, suitable for geophysical fields.  相似文献   

On the structure of the interplanetary magnetic field under non-stationary boundary conditions     

Ludmila Třísková  Igor S. Veselovskij  Reviewer L. Křivský 《Studia Geophysica et Geodaetica》1988,32(4):362-367

Summary The structure of the interplanetary magnetic field (IMF) is investigated theoretically in a kinematic approximation under frozen-in conditions in the solar wind and non-stationary boundary conditions. As an example, a time-dependent model of the IMF, created in the case of a change of the general magnetic field of the Sun represented by the dipole term, is analyzed. Very simple assumptions as to the field of velocities in the solar wind are made. The results show the formation of zero IMF points of two types(O, X). Points of theO-type are formed and move radially in the equatorial plane. They are surrounded by magnetic clouds with loops of lines of force. Points of theX-type are formed and move radially above the poles.

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muu u¶rt;aa mma nam aum n() uamu nuuuu nu uu mu m u mauaau uu. am nua ama ¶rt; , ua nu uuu aum n a, n¶rt;ma ¶rt;un , auu m u. mum n m m ¶rt;a nmu n¶rt;nu. mam naam aau m ¶rt; mun(O, X). uO-muna uam u ¶rt;um a¶rt;ua amua nmu. u aumu aau nmu u uu. uX-muna uam u ¶rt;um a¶rt;ua a¶rt; nau.

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Optimum processing of gravimetric observations affected by the drift in a one-stage net,and the analysis of the accuracy of the results     

Ludmila Kubáčková  Reviewer M. Pick 《Studia Geophysica et Geodaetica》1986,30(3):236-241

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.

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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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КРИТИКА     

Ludmila Kubáčková  Miloslav Kopecký 《Studia Geophysica et Geodaetica》1985,29(4):415-416

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Kimberlites distribution in Angola and prospective areas for new discoveries     

Ustinov  Victor N.  Feijo Bartolomeu  Ana M.  Zagainy  Alexander K.  Felix  Joao T.  Mikoev  Igor I.  Stegnitskiy  Yury B.  Lobkova  Ludmila P.  Kukui  Irina M.  Nikolaeva  Evelina V.  Antonov  Sergei A. 《Mineralogy and Petrology》2018,112(2):383-396

Based on a comprehensive analysis of kimberlite pipes of Angola, including the near surface structural setting, deep lithospheric structure, pipe morphology and emplacement, mineralogical and petrographic features, diamond characteristics and locations of secondary deposits four geographical regions have been outlined within Angola representing four types of diamond bearing potential. These areas include high diamond bearing potential pipes, possible potential, no potential, and unclear potential areas. It was found that the depth of magmatism and diamond potential of kimberlites increases from the Atlantic coast in southwestern Angola into the continent in the north-easterly direction. Areas prospective for the discovery of new primary diamond deposits have been identified.

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Trophic relations of capelin Mallotus villosus and polar cod Boreogadus saida in the Barents Sea as a factor of impact on the ecosystem     

Emma L. Orlova  Andrey V. Dolgov  Galina B. Rudneva  Ivan A. Oganin  Ludmila L. Konstantinova 《Deep Sea Research Part II: Topical Studies in Oceanography》2009,56(21-22):2054

The purpose of the study is to assess the role of trophic relations of the dominant pelagic fishes capelin and polar cod in the Barents Sea with regard to distribution and accessibility as prey for the Atlantic cod in warm years (2004–2005). Unlike in the previous period, during these warm years a dramatic increase of the polar cod population resulted in a northwards expansion of the feeding grounds where overlapping of polar cod and capelin concentrations was observed. This caused an increased competition for copepods, which are the main food item for young fish. In the areas dominated by polar cod the shortage of copepods forced immature capelin to switch to the chaetognath Sagitta, which affected their fatness negatively.During the warm years the feeding grounds of Atlantic cod also expanded, to a large degree caused by the shortage of their main food, the capelin. In 2004–2005 the cod formed feeding concentrations in the north and northeast Barents Sea where they fed on the capelin. In this area the consumption of polar cod by cod increased, and in some local areas the polar cod practically replaced the capelin in the diet of cod. In general polar cod in the diet of Atlantic cod were more important in the northern than in the southern part of the Barents Sea. The fatness of cod was extremely low during the whole spring–summer period (until August), and after the feeding period the fatness index of the Atlantic cod became lower than the average long-term autumn value.  相似文献   

Groundwater and surface water connectivity within the recharge area of Guarani aquifer system during El Niño 2014–2016          下载免费PDF全文

Ludmila Vianna Batista  Didier Gastmans  Ricardo Sánchez‐Murillo  Bárbara Saeta Farinha  Sarah Maria Rodrigues dos Santos  Chang Hung Kiang 《水文研究》2018,32(16):2483-2495

Recharge areas of the Guarani Aquifer System (GAS) are particularly sensitive and vulnerable to climate variability; therefore, the understanding of infiltration mechanisms for aquifer recharge and surface run‐off generation represent a relevant issue for water resources management in the southeastern portion of the Brazilian territory, particularly in the Jacaré‐Pepira River watershed. The main purpose of this study is to understand the interactions between precipitation, surface water, and groundwater using stable isotopes during the strong 2014–2016 El Niño Southern Oscillation event. The large variation in the isotopic composition of precipitation (from ?9.26‰ to +0.02‰ for δ¹⁸O and from ?63.3‰ to +17.6‰ for δ²H), mainly associated with regional climatic features, was not reflected in the isotopic composition of surface water (from ?7.84‰ to ?5.83‰ for δ¹⁸O and from ?49.7‰ to +33.6‰ for δ²H), mainly due to the monthly sampling frequency, and groundwater (from ?7.04‰ to ?7.76‰ for δ¹⁸O and from ?49.5‰ to ?44.7‰ for δ²H), which exhibited less variation throughout the year. However, variations in deuterium excess (d‐excess) in groundwater and surface water suggest the occurrence of strong secondary evaporation during the infiltration process, corresponding with groundwater level recovery. Similar isotopic composition in groundwater and surface water, as well as the same temporal variations in d‐excess and line‐conditioned excess denote the strong connectivity between these two reservoirs during baseflow recession periods. Isotopic mass balance modelling and hydrograph separation estimate that the groundwater contribution varied between 70% and 80%, however, during peak flows, the isotopic mass balance tends to overestimate the groundwater contribution when compared with the other hydrograph separation methods. Our findings indicate that the application of isotopic mass balance methods for ungauged rivers draining large groundwater reservoirs, such as the GAS outcrop, could provide a powerful tool for hydrological studies in the future, helping in the identification of flow contributions to river discharge draining these areas.  相似文献   

Seismicity in the far Arctic areas: Severnaya Zemlya and the Taimyr Peninsula     

Morozov  Alexey N.  Vaganova  Natalya V.  Konechnaya  Yana V.  Asming  Vladimir E.  Dulentsova  Ludmila G.  Evtyugina  Zinaida A. 《Journal of Seismology》2021,25(5):1171-1188

Journal of Seismology - A permanent seismic station was for the first time installed on Severnaya Zemlya in the Russian Arctic. This made it possible to record low-magnitude earthquakes occurring...  相似文献