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111.
This study extends the application of local spatial nonparametric prediction models to the estimation of recoverable gas volumes
in continuous-type gas plays to regimes where there is a single geologic trend. A transformation is presented, originally
proposed by Tomczak, that offsets the distortions caused by the trend. This article reports on numerical experiments that
compare predictive and classification performance of the local nonparametric prediction models based on the transformation
with models based on Euclidean distance. The transformation offers improvement in average root mean square error when the
trend is not severely misspecified. Because of the local nature of the models, even those based on Euclidean distance in the
presence of trends are reasonably robust. The tests based on other model performance metrics such as prediction error associated
with the high-grade tracts and the ability of the models to identify sites with the largest gas volumes also demonstrate the
robustness of both local modeling approaches.
相似文献
Emil D. AttanasiEmail: |
112.
Emil Blias 《Geophysical Prospecting》2009,57(3):323-341
Lateral velocity changes (velocity anomalies) in the overburden may cause significant oscillations in normal moveout velocities. Explicit analytical moveout formulas are presented and provide a direct explanation of these lateral fluctuations and other phenomena for a subsurface with gentle deep structures and shallow overburden anomalies. The analytical conditions for this have been derived for a depth-velocity model with gentle structures with dips not exceeding 12°. The influence of lateral interval velocity changes and curvilinear overburden velocity boundaries can be estimated and analysed using these formulas. An analytical approach to normal moveout velocity analysis in a laterally inhomogeneous medium provides an understanding of the connection between lateral interval velocity changes and normal moveout velocities. In the presence of uncorrected shallow velocity anomalies, the difference between root-mean-square and stacking velocity can be arbitrarily large to the extent of reversing the normal moveout function around normal incidence traveltimes. The main reason for anomalous stacking velocity behaviour is non-linear lateral variations in the shallow overburden interval velocities or the velocity boundaries.
A special technique has been developed to determine and remove shallow velocity anomaly effects. This technique includes automatic continuous velocity picking, an inversion method for the determination of shallow velocity anomalies, improving the depth-velocity model by an optimization approach to traveltime inversion (layered reflection tomography) and shallow velocity anomaly replacement. Model and field data examples are used to illustrate this technique. 相似文献
A special technique has been developed to determine and remove shallow velocity anomaly effects. This technique includes automatic continuous velocity picking, an inversion method for the determination of shallow velocity anomalies, improving the depth-velocity model by an optimization approach to traveltime inversion (layered reflection tomography) and shallow velocity anomaly replacement. Model and field data examples are used to illustrate this technique. 相似文献
113.
In this work, we address the Black Sea setup of Nucleus for European Modelling of the Ocean (NEMO), and in particular some
model enhancements associated with the most important characteristic of ocean dynamics in this semi-enclosed basin, that is
the sea-level variability and its relationship with water cycles and wind. Forcing data are presented in detail and compared
with previously used coarser-resolution data. One emphasis in this paper is on the statistical analyses of forcing data and
outputs from simulations with a focus on the sea level and its change. Numerical simulations are carried out as free run,
and alternatively, altimeter data assimilation based on displacement of water properties in the pycnocline is used. Comparisons
between the two runs identify the robustness of circulation driven by water balance and winter intensification. Problems in
the model to replicate the redistribution of water properties between the two sub-basins in free-run mode are also discussed,
which are observed during years with extreme climatic conditions. 相似文献
114.
Under assumption of the closed FRW-universe, the idea is presented that the cosmological expansion/contraction on its own, has an entropy balancing effectively the changing entropy of the cosmic fluid in such a way that at every epoch the total entropy of the Universe remains constant. 相似文献
115.
Emil O. Frind 《Advances in water resources》1982,5(2):89-97
The problem of seawater intrusion in a confined coastal aquifer is investigated. The aquifer is overlain by a leaky aquitard and both units extend continuously out under the sea. The problem is formulated in terms of the two governing differential equations, the fluid continuity equation written conveniently in terms of equivalent freshwater head, and the mass continuity equation. Use of linear rectangular finite elements, with direct integration and an iterative solution technique lead to an efficient numerical scheme that is capable of handling long simulation periods. The results, for a 300 m thick aquifer overlain by a 100 m thick aquitard, show that the aquitard has a controlling influence on the salt distribution. A zone of mixing in the aquifer is found to extend for several kilometres in the seaward as well as the landward direction. The time period required by the system to attain a state of dynamic equilibrium after a perturbation is applied may be of the order of centuries. The aquitard is found to cause a downward and seaward displacement of the average salt front. 相似文献
116.
Unmanned aerial vehicles (UAV) for assessment of qualitative classification of Norway spruce in temperate forest stands 总被引:1,自引:0,他引:1
AbstractThe study investigates the potential of UAV-based remote sensing technique for monitoring of Norway spruce health condition in the affected forest areas. The objectives are: (1) to test the applicability of UAV visible an near-infrared (VNIR) and geometrical data based on Z values of point dense cloud (PDC) raster to separate forest species and dead trees in the study area; (2) to explore the relationship between UAV VNIR data and individual spruce health indicators from field sampling; and (3) to explore the possibility of the qualitative classification of spruce health indicators. Analysis based on NDVI and PDC raster was successfully applied for separation of spruce and silver fir, and for identification of dead tree category. Separation between common beech and fir was distinguished by the object-oriented image analysis. NDVI was able to identify the presence of key indicators of spruce health, such as mechanical damage on stems and stem resin exudation linked to honey fungus infestation, while stem damage by peeling was identified at the significance margin. The results contributed to improving separation of coniferous (spruce and fir) tree species based on VNIR and PDC raster UAV data, and newly demonstrated the potential of NDVI for qualitative classification of spruce trees. The proposed methodology can be applicable for monitoring of spruce health condition in the local forest sites. 相似文献
117.
Jaromír Ulrych Emil Jelínek Zdeněk Řanda Felicity E. Lloyd Kadosa Balogh Ernst Hegner Jiří K. Novák 《Chemie der Erde / Geochemistry》2010,70(4):319-333
High-Ti melanephelinite (3.8–5.9 wt% TiO2), medium-Ti (phono)tephrite (2.7–3.1 wt% TiO2), and low-Ti olivine melanephelinite/basanite (1.9–2.3 wt.% TiO2) are subordinate rock types in the central European Cenozoic Volcanic Province. A contrasting melanephelinite to (phono)tephrite series occurs in the Lou?ná–Oberwiesenthal Volcanic Centre (37–28 Ma) and also as satellite volcanic bodies (26–12 Ma) together with olivine melanephelinite/basanite (17–20 Ma) on the southwestern periphery of the Kru?né hory mountains (Erzgebirge). The volcanic rocks intrude the Variscan basement of the uplifted shoulder of the Oh?e/Eger Rift in the Kru?né hory mountains of the Bohemian Massif. Low Mg# (44–59) and Cr, Ni contents and enrichment of LILE, Zr, Hf, Nb, Ta, U, Th and LREE in the high-Ti melanephelinites contrast with the composition of primitive low-Ti olivine melanephelinites/basanites displaying high Mg# (63–74) and high contents of compatible elements. The high-Ti melanephelinites reveal a wide range in initial 87Sr/86Sr of ca. 0.7034–0.7038 and εNd of 2.4–4.9. The low-Ti melanephelinites show an overlapping range of initial 87Sr/86Sr of ca. 0.7035–0.7036 and εNd of 4.3–5.5. The large variation in initial 87Sr/86Sr ratios at similar εNd values in those rock types is interpreted as evidence for melting of metasomatized lithospheric mantle sources comprising K-bearing phases with radiogenic Sr. Modification of the olivine-free alkali basaltic magmas by differentiation or crustal contamination could give rise to the medium-Ti (phono) tephrites. The initial isotope ratios of all samples are consistent with HIMU-mantle sources and contributions from lithospheric mantle. The olivine-free melanephelinitic rocks often contain alkali pyroxenite–ijolite xenoliths with initial 87Sr/86Sr ratios of ca. 0.7036 and εNd of 3.0. We interpret these xenoliths as samples of an intra-crustal alkali complex derived from similar mantle sources as those for the basaltic volcanic rocks. 相似文献
118.
Pavla Kováříková Wolfgang Siebel Emil Jelínek Miroslav Štemprok Václav Kachlík František V. Holub Vratislav Blecha 《International Journal of Earth Sciences》2010,99(3):545-565
Mafic and intermediate intrusions occur in the Slavkovsky les as dykes, sills and minor tabular bodies emplaced in metamorphic
rocks or enclosed in late Variscan granites near the SW contact of the Western Krušné hory/Erzgebirge granite pluton. They
are similar in composition and textures to the redwitzites defined in NE Bavaria. Single zircon Pb-evaporation analyses constrain
the age of a quartz monzodiorite at 323.4 ± 4.4 Ma and of a granodiorite at 326.1 ± 5.6 Ma. The P–T range of magma crystallization is estimated at ~1.4–2.2 kbar and ~730–870°C and it accords with a shallow intrusion level
of late Variscan granites but provides lower crystallization temperatures compared to the Bavarian redwitzites. We explain
the heterogeneous composition of dioritic intrusions in the Slavkovsky les by mixing between mafic and felsic magmas with
a minor effect of fractional crystallization. Increased K, Ba, Rb, Sr and REE contents compared to tholeiitic basalts suggest
that the parental mafic magma was probably produced by melting of a metasomatised mantle, the melts being close to lamprophyre
or alkali basalt composition. Diorites and granodiorites originated from mixed magmas derived by addition of about 25–35 and
50 vol.%, respectively, of the acid end-member (granite) to lamprophyre or alkali-basalt magma. Our data stress an important
role of mafic magmas in the origin of late Variscan granitoids in NW Bohemian Massif and emphasize the effect of mantle metasomatism
on the origin of K-rich mafic igneous rocks. 相似文献
119.
Water intrusions and particle signatures in the Black Sea: a Biogeochemical-Argo float investigation
Emil Vassilev Stanev Sebastian Grayek Hervé Claustre Chaterine Schmechtig Antoine Poteau 《Ocean Dynamics》2017,67(9):1119-1136
Continuous observations during 3 years with a vertical resolution of 1 dbar from two Bio-Argo floats in the Black Sea that were equipped with oxygen optodes, chlorophyll fluorometers, and backscattering sensors are analyzed. The particle backscattering coefficient, b bp provides a proxy for the concentration of suspended particles. The observations clearly identify thermal and b bp intrusions down to ~700–800 m in the Bosporus inflow area. In this area, b bp is more than five times larger than elsewhere, which could indicate bacterial abundance and possible biological involvement in the precipitation of Mn-containing particles. The b bp anomalies become much shallower than the temperature anomalies with increasing distance to the east of the strait. Their maxima are located between the onset of the suboxic zone and the upper part of the anoxic layer. Unlike well-known intrusions that are caused by inflow, open ocean intrusions are shallower and often characterized by multiple layers of backscatter maxima with thicknesses of only 15–20 m. The ratio between backscattering coefficients measured at two wavelengths, which gives a proxy for particle size, shows that the relative amount of larger size particles in the anoxic layer increases with depth. The particle concentrations and their size distribution display different vertical variability, which indicates the complex transformation of biological matter. The lower concentration of particles and lower chlorophyll-a during the extremely warm 2016 reveals an overall positive correlation between the two properties. The trends in the particle backscattering coefficient in the suboxic zone during 2013–2016 could indirectly reveal a biogeochemical response to temperature changes. 相似文献
120.
Sara Jutterström Emil Jeansson Leif G. Anderson E. Peter Jones James H. Swift 《Progress in Oceanography》2008,78(1):78-84
Several methods to compute the anthropogenic component of total dissolved inorganic carbon () in the ocean have been reported, all in some way deducing (a) the effect by the natural processes, and (b) the background concentration in the pre-industrial scenario. In this work we present a method of calculating using nutrient and CFC data, which takes advantage of the linear relationships found between nitrate (N), phosphate (P) and CFC-11 in the Nordic Seas sub-surface waters. The basis of the method is that older water has lower CFC-11 concentration and also has been exposed to more sinking organic matter that has decayed, resulting in the slopes of P versus CFC-11 and N versus CFC-11 being close to the classic Redfield ratio of 1:16. Combining this with the slope in total alkalinity (AT) versus CFC-11 to correct for the dissolution of metal carbonates gives us the possibility to deduce the concentration of anthropogenic CT in the Nordic Seas. This further allowed us to compute the inventory of anthropogenic CT below 250 m in the Nordic Seas in spring 2002, to ∼1.2 Gt C. 相似文献