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The Most Frequent Value Method (MFV) is applied to groundwater modeling as a robust and effective geostatistical method. The Most Frequent Value method is theoretically derived from the minimization of the information loss called the I-divergence. The MFV algorithm is then coupled with global optimization (Very Fast Simulated Annealing) to provide a powerful method for solving the inverse problems in groundwater modeling. The advantages and applicability of this new approach are illustrated by means of theoretical investigations and case studies. It is demonstrated that the MFV method has certain advantages over the conventional statistical methods derived from the maximum likelihood principle.
Resumen El Método del Valor Mas Frecuente (VMF), es aplicado al modelamiento de agua subterránea, como un método geoestadístico simple y efectivo. Este método es derivado teóricamente de la acción de reducir al mínimo la pérdida de información, llamada así divergencia – I. El algoritmo del VMF es entonces acoplado con optimización global(Very Fast Simulated Annealing), para obtener así un método efectivo que resuelva los problemas inversos en el modelamiento de aguas subterráneas. Las ventajas y aplicabilidad de esta aproximación nueva son ilustradas a través de investigaciones teóricas y estudios de caso. Se demuestra que el método VMF tiene ciertas ventajas sobre los métodos estadísticos convencionales derivados del principio de la probabilidad máxima.
Résumé On a appliqué la méthode de la valeur la plus fréquente (VPF) comme une méthode géostatistique robuste et efficace pour modéliser les eaux souterraines. Du point de vue théorique, la méthode de VPF part de la minimisation de linformation perdue, dénommée I-divergence. On couple après lalgorithme de la méthode de VPF avec la méthode doptimisation globale affin de réaliser une méthode performante pour résoudre le problème inverse dans le domaine des eaux souterraine. Les avantages et les possibilités dapplication de cette nouvelle approche sont illustrées par des investigations théoriques, ainsi que par des études de cas. On montre que la méthode de VPF présente certains avantages par rapport des méthodes statistiques conventionnelles basées sur le principe de la probabilité maximale.相似文献
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Olga V. Sidorova Matthias Saurer Vladimir S. Myglan Anja Eichler Margit Schwikowski Aleksander V. Kirdyanov Marina V. Bryukhanova Oksana V. Gerasimova Ivan A. Kalugin Andrey V. Daryin Rolf T. W. Siegwolf 《Climate Dynamics》2012,38(1-2):175-188
For the first time we present a multi-proxy data set for the Russian Altai, consisting of Siberian larch tree-ring width (TRW), latewood density (MXD), δ13C and δ18O in cellulose chronologies obtained for the period 1779–2007 and cell wall thickness (CWT) for 1900–2008. All of these parameters agree well between each other in the high-frequency variability, while the low-frequency climate information shows systematic differences. The correlation analysis with temperature and precipitation data from the closest weather station and gridded data revealed that annual TRW, MXD, CWT, and δ13C data contain a strong summer temperature signal, while δ18O in cellulose represents a mixed summer and winter temperature and precipitation signal. The temperature and precipitation reconstructions from the Belukha ice core and Teletskoe lake sediments were used to investigate the correspondence of different independent proxies. Low frequency patterns in TRW and δ13C chronologies are consistent with temperature reconstructions from nearby Belukha ice core and Teletskoe lake sediments showing a pronounced warming trend in the last century. Their combination could be used for the regional temperature reconstruction. The long-term δ18O trend agrees with the precipitation reconstruction from the Teletskoe lake sediment indicating more humid conditions during the twentieth century. Therefore, these two proxies could be combined for the precipitation reconstruction. 相似文献
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Mineralium Deposita - 相似文献
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Anja Eichler Willy Tinner Sabina Brütsch Susanne Olivier Tatyana Papina Margit Schwikowski 《Quaternary Science Reviews》2011,30(9-10):1027-1034
Forest fires play a key role in the global carbon cycle and thus, can affect regional and global climate. Although fires in extended areas of Russian boreal forests have a considerable influence on atmospheric greenhouse gas and soot concentrations, estimates of their impact on climate are hampered by a lack of data on the history of forest fires. Especially regions with strong continental climate are of high importance due to an intensified development of wildfires. In this study we reconstruct the fire history of Southern Siberia during the past 750 years using ice-core based nitrate, potassium, and charcoal concentration records from Belukha glacier in the continental Siberian Altai. A period of exceptionally high forest-fire activity was observed between AD 1600 and 1680, following an extremely dry period AD 1540–1600. Ice-core pollen data suggest distinct forest diebacks and the expansion of steppe in response to dry climatic conditions. Coherence with a paleoenvironmental record from the 200 km distant Siberian lake Teletskoye shows that the vegetational shift AD 1540–1680, the increase in fire activity AD 1600–1680, and the subsequent recovery of forests AD 1700 were of regional significance. Dead biomass accumulation in response to drought and high temperatures around AD 1600 probably triggered maximum forest-fire activity AD 1600–1680. The extreme dry period in the 16th century was also observed at other sites in Central Asia and is possibly associated with a persistent positive mode of the Pacific Decadal Oscillation (PDO). No significant increase in biomass burning occurred in the Altai region during the last 300 years, despite strongly increasing temperatures and human activities. Our results imply that precipitation changes controlled fire-regime and vegetation shifts in the Altai region during the past 750 years. We conclude that high sensitivity of ecosystems to occasional decadal-scale drought events may trigger unprecedented environmental reorganizations under global-warming conditions. 相似文献
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Facies and geochemical correlations in the Upper Hauptdolomit (Norian) of the eastern Lechtaler Alps
An unusually thick (over 1000 m) inter- to infratidal, calcareous, facies development in the Upper Hauptdolomit (Norian) of the eastern Lechtaler Alps, northern Tyrol, was investigated. The special litho- and bio-facies are described in two sections (A and B) and are compared with some geochemical parameters.With reference to Fischer's (1965) original concept, these special facies are shown to correspond, in many details, to the restricted environments of the Trucial Coast, Persian Gulf. Based on previously published ideas (Fischer, 1965; Zankl, 1967, 1971), the special facies development of the Upper Hauptdolomit (Hd) of the eastern Lechtaler Alps can be schematically correlated with the Norian Dachsteinkalk facies: the investigated sections appear to represent the transitional facies between wide supratidal flats (typical Hd) and the less restricted facies of the shallow-marine Dachsteinkalk platform.The paper shows a statistical comparison of the interrelationships of Ca/Mg, Mn, Fe, Zn and insoluble residue, based on correlation coefficients. This data is related to facies. 相似文献
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