Influence of atmospheric circulation on precipitation in Altai Mountains   总被引：2，自引：0，他引：2  

Natalia Malygina  Tatiana Papina  Nina Kononova  Tatiana Barlyaeva 《山地科学学报》2017,14(1):46-59

We analyzed the changes in precipitation regime in the Altai Mountains for 1959-2014 and estimate the influence of atmospheric circulations on these changes. Our study showed that during last 56 years the changes in the precipitation regime had a positive trend for the warm seasons(April-October),but weakly positive or negative trends for the cold seasons(November-March). It was found that these changes correspond to the decreasing contribution of “Northern meridional and Stationary anticyclone(Nm-Sa)” and “Northern meridional and East zonal(Nm-Ez)” circulation groups and to the increasing contribution of “West zonal and Southern meridional(Wz-Sm)” circulation groups,accordingly to the Dzerdzeevskii classification. In addition,it was found that the variation of precipitation has a step change point in 1980. For the warm seasons,the precipitation change at this point is associated with the reduced influence of “West zonal(Wz)”,“Northern meridional and Stationary anticyclone(Nm-Sa)” and “Northern meridional and Southern meridional(Nm-Sm)” circulation groups. For the cold seasons,a substantialincrease of “Wz-Sm” and a decrease of “Nm-Sa”,“Nm-Ez” circulation groups are responsible for the precipitation change in the two time periods(1959-1980 and 1981-2014).  相似文献   

Wavelet analysis for the regional-residual and local separation of potential field anomalies   总被引：1，自引：0，他引：1  

Maurizio Fedi  Tatiana Quarta 《Geophysical Prospecting》1998,46(5):507-525

A method based on the discrete wavelet transform was applied to the regional-residual separation of potential fields and to the filtering of local anomalies. A specific space-scale wavelet analysis, called multiresolution analysis, allowed decomposition of the signal with respect to a vast range of scales. Different analysing wavelets were applied to anomalies in both synthetic and real cases, but the more appropriate basis needed to be chosen by requiring the maximum compactness for the multiresolution analysis. Moreover, since such analysis was found not to be shift-invariant, the same criterion was applied to choosing the best signal shift. Application of the technique to both synthetic and real cases produced an optimal space-scale representation of the fields and a consistent regional-residual separation. Furthermore, the space localization allowed a variety of filtered signals to be obtained, each one with a specific scale and local area content. Fourier and wavelet analyses were both applied to the filtering out of the intense Etna anomaly from the aeromagnetic field of Sicily. The wavelet method was more powerful, suppressing only the Etna volcano anomaly and leaving the rest of the map practically unchanged.  相似文献   

Groundwater resources of the middle and upper Odra River basin, southwestern Poland     

Tatiana Bochenska  Henryk Marszalek  Lech Poprawski 《Hydrogeology Journal》1998,6(2):315-322

 The total amount of groundwater resources in the middle and upper Odra River basin is 5200×10³ m³/d, or about 7.7% of the disposable groundwater resources of Poland. The average modulus of groundwater resources is about 1.4 L/s/km². Of the 180 'Major Groundwater Basins' (MGWB) in Poland, 43 are partly or totally located within the study area. The MGWB in southwestern Poland have an average modulus of groundwater resources about 2.28 L/s/km² and thus have abundant water resources in comparison to MGWB from other parts of the country. Several types of mineral waters occur in the middle and upper Odra River basin. These waters are concentrated especially in the Sudety Mountains. Carbon-dioxide waters, with yields of 414 m³/h, are the most widespread of Sudetic mineral waters. The fresh waters of the crystalline basement have a low mineralization, commonly less than 100 mg/L; they are a HCO₃–Ca–Mg or SO₄–Ca–Mg type of water. Various hydrochemical compositions characterize the groundwater in sedimentary rocks. The shallow aquifers are under risk of atmospheric pollution and anthropogenic effects. To prevent the degradation of groundwater resources in the middle and upper Odra River basin, Critical Protection Areas have been designated within the MGWB. Received, January 1995 Revised, May 1996, August 1997 Accepted, August 1997  相似文献   

Three Decades of Seismic Activity at Mt. Vesuvius: 1972–2000     

Giuseppe De?Natale  Igor?Kuznetzov  Tatiana?Kronrod  Antonella?PeresanEmail author  Angela?Saraò  Claudia?Troise  Giuliano F.?Panza 《Pure and Applied Geophysics》2004,161(1):123-144

We analyse the seismic catalogue of the local earthquakes which occurred at Somma-Vesuvius volcano in the past three decades (1972–2000). The seismicity in this period can be described as composed of a background level, characterised by a low and rather uniform rate of energy release and by sporadic periods of increased seismic activity. Such relatively intense seismicity periods are characterised by energy rates and magnitudes progressively increasing in the critical periods. The analysis of the b value in the whole period evidences a well-defined pattern, with values of b progressively decreasing, from about 1.8 at the beginning of the considered period, to about 1.0 at present. This steady variation indicates an increasing dynamics in the volcanic system. Within this general trend it is possible to identify a substructure in the time sequence of the seismic events, formed by the alternating episodes of quiescence and activity. The analysis of the source moment tensor of the largest earthquakes shows that the processes at the seismic source are generally not consistent with simple double-couples, but that they are compatible with isotropic components, mostly indicating volumetric expansion. These components are shown to be statistically significant for most of the analysed events. Such focal mechanisms can be interpreted as the effect of explosion phenomena, possibly related to volatile exsolution from the crystallising magma. The availability of a reduced amount of high quality data necessary for the inversion of the source moment tensor, the still limited period of systematic observation of Vesuvius micro-earthquakes and, above all, the absence of eruptive events during such interval of time, cannot obviously permit the outlining of any formal premonitory signal. Nevertheless, the analysis reported in this paper indicates a progressively evolving dynamics, characterised by a generally increasing trend in the seismic activity in the volcanic system and by a significant volumetric component of recent major events, thus posing serious concern for a future evolution towards eruptive activity.  相似文献   

Weighting and smoothing of stomach content data as input for MSVPA with particular reference to the Barents Sea     

Bulgakova  Tatiana; Vasilyev  Dmitri; Daan  Niels 《ICES Journal of Marine Science》2001,58(6):1208-1218

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A geophysical survey of the Spitsbergen Margin and surrounding areas     

Dmitry Baturin  Tatiana Fedukhina  Leo Savostin  Artem Yunov 《Marine Geophysical Researches》1994,16(6):463-484

New geophysical information including multichannel seismic profiling data obtained by the PGO Sevmorgeologia Ministry of Geology of the former USSR, Murmansk during 1984–1988 is discussed and interpreted in this study. The deep structure, sedimentary cover and stratigraphy of the Spitsbergen Continental Margin, considered to be a passive margin, i.e. divergent in the northern part and strike-slip in the western part, is described.Two genetically different types of plateaus on the continental margin, Yermak in the north and Spitsbergen (Vestnesa) in the west, have been identified.The entire extent of the continental slope of the northern part of the Spitsbergen Continental Margin in the Eurasia Basin is underlain by attenuated continental crust, while at the base of the Southwest Continental Margin, the oceanic crust along almost the entire extent is observed. The sedimentary cover, up to 10 km thick within the West Spitsbergen Continental Margin, is likewise observed. Within the North Spitsbergen Margin, however, it does not exceed 3.5 km in thickness.The extension and deposition within the West Spitsbergen Margin began in early Oligocene, while the rifting with accompanying sedimentation within the North Spitsbergen Continental Margin started probably in Early Cretaceous.  相似文献   

Development of the Verkhoyansk-Kolyma orogenic system as a result of interaction of adjacent continental and oceanic plates     

N. I. Filatova  V. E. Khain 《Geotectonics》2008,42(4):258-285

The Mid-Cretaceous Verkhoyansk-Chukchi Tectonic Domain is characterized by fanlike diverging systems of tectonic sheets and imbricate thrusts verging to the two framing continents. The Verkhoyansk and New Siberian-Chukchi-Brooks Fold-Thrust systems of the deformed margins of the Siberian and Hyperborean-North American continents, respectively, adjoin the inner Verkhoyansk-Kolyma Collision System. The above fold-thrust systems include the Verkhoyansk and Colville foredeeps coeval with thrusting. The Verkhoyansk-Kolyma Fold-Nappe System is composed of Cambrian to Upper Jurassic oceanic, marginal-sea, and island-arc complexes and bounded by a collision suture consisting of the Kolyma Loop abutted on the South Anyui segment along a left-lateral strike-slip fault. The inner root zone and the outer zone of nappes overthrusting the adjacent continents are distinguished in the suture. Several levels of structural unconformities, olistostrome-molasse sequences, and zones of amphibolite-greenschist metamorphism coeval with thrusting correspond to particular stages in the evolution of the Verkhoyansk-Kolyma System. The Neoproterozoic and Early Paleozoic oceans closed during the Baikalian and Caledonian orogenies. The Alazeya-South Anyui-Angayucham ocean that evolved from the Devonian to the Late Jurassic was subject to gradual closure against the background of trilateral compression during convergence of the Siberian and Hyperborean-North American cratons and accretion and collision along the Pacific margin. The fold-nappe structure of the Verkhoyansk-Kolyma Orogen and the boundary collision suture were disturbed by left-lateral strike-slip faults during Mid-Cretaceous compression, and the South Anyui segment of the suture was displaced to the northwest along the strike-slip fault. The Mid-Cretaceous Orogeny at the Pacific margin gave rise to meridional compression of its back zone and latitudinal squashing of the Verkhoyansk-Kolyma Orogen with formation of the Kolyma and Kobuk looplike limitations.  相似文献   

Specifics of magmatism in marginal continental and marginal-sea pull-apart basins: Western periphery of the Pacific Ocean     

N. I. Filatova 《Petrology》2008,16(5):448-467

The paper presents data on pull-apart (synchronous with strike-slip faulting) extensional structures formed in relation to Indo-Eurasian collision and including continental marginal rifts in East Asia and adjacent marginal sea basins. The evolution of Cenozoic pull-apart basins (developing synchronously with strike-slip faulting) in the western surroundings of the Pacific ocean corresponds to a basaltoid sequence in which the onset of rifting and the stage of maximum extension are marked by the first and last members of this sequence that have, respectively, calc-alkaline and tholeiitic depleted composition. The predominance of intermediate members with mixed isotopic-geochemical signatures testifies to the interaction of diverse magmatic melts. The opening of pull-apart basins (including those of marginal sea) was associated with magmatism whose sources were localized, judging from geochemical indicators, in the modified continental lithospheric mantle and depleted asthenosphere. The sources in the lithospheric mantle that was affected by long-lasting metasomatic recycling in the geological past dominated during the initial stages of continental extension and gave way to depleted asthenospheric sources. This model is consistent with the deep structure of the territories: extensional basins correspond to asthenospheric upwelling, with the ascent of asthenospheric diapirs positively correlated with the intensity of extension of the continental lithosphere and the degree of depletion of the accumulated basaltoids. The discovery of widespread calc-alkaline rocks (which are genetically related to the ancient metasomatized lithospheric mantle) in zones of continental rifting and marginal basins of the strike-slip fault nature significantly broadens the compositional range of volcanics typical of extensional geodynamic environments. At the same time, this testifies to the polygeodynamic nature of calc-alkaline volcanics, which can accumulate without any relations with coeval subduction zones.  相似文献   

Multiple-Point Simulations Constrained by Continuous Auxiliary Data   总被引：8，自引：5，他引：3  

Tatiana L. Chugunova  Lin Y. Hu 《Mathematical Geosciences》2008,40(2):133-146

An important issue of using the multiple-point (MP) statistical approach for reservoir modeling concerns the integration of auxiliary constraints derived, for instance, from seismic information. There exist two methods in the literature for these non-stationary MP simulations. One is based on an analytical approximation (the “τ-model”) of the conditional probabilities that involve auxiliary data. The degree of approximation with this method depends on the parameter τ, whose inference is difficult in practice. The other method is based on the inference of these conditional probabilities directly from training images. This method classifies the auxiliary data into a few classes. This classification is in general arbitrary and therefore inconvenient in practice, especially in the case of continuous auxiliary constraints. In this paper, we propose an alternative method for performing non-stationary MP simulations. This method accounts for the data support in the modeling procedure and allows, in particular, continuous auxiliary data to be integrated into MP simulations. This method avoids the major limitations of the previous methods, namely the use of an approximate analytical model and the reduction of the auxiliary data into a limited number of classes. This method can be easily implemented in the existing MP simulation codes. Numerical tests show good performance of this method both in reproducing the geometrical features of the training image and in honouring the auxiliary data.  相似文献   

The role of life‐history traits,selective pressure and hydrographic boundaries in shaping the genetic structure of the transparent goby,Aphia minuta          下载免费PDF全文

Paolo Ruggeri  Andrea Splendiani  Massimo Giovannotti  Tatiana Fioravanti  Giulia Occhipinti  Paola Nisi Cerioni  Vincenzo Caputo Barucchi 《Marine Ecology》2016,37(3):518-531

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