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11.
The sequential extraction procedure was proposed and used to study of mercury speciation in real samples of soil. Samples
of soil profiles together with bedrock and coal were taken from sampling spots in the vicinity of surficial coal beds in an
area with natural coal outcrops. The proposed sequential extraction procedure involves the following fractionation: organic
mercury compounds, extractable mercury in an acidic medium, mercury bound to humic substances, elemental Hg and mercury bound
to complexes, HgS and residual mercury. The significant distribution of mercury between the two portions—mercury bound to
humic substance and HgS was determined in the majority of samples. The mercury bound to humic substances created a significant
contribution, especially to the top layer of soil. On the other hand, HgS was the dominant form in the samples from lower
layers of the soil profile. The mercury content in the samples did not show a distinct mobility. The influence of soil parameters
on the mercury distribution in the studied samples was investigated and discussed. 相似文献
12.
Paleogeography of the Early Badenian connection between the Vienna Basin and the Carpathian Foredeep
The paleogeographic reconstruction for an early Badenian connection of the Vienna Basin and the Carpathian Foredeep in the Mikulov area (Mikulov Gate) based on paleontological (otoliths) and geological (regional geology, tectonics) data has been provided. The ecologically homogenous deep water associations of otoliths in the most NW tip of the Vienna Basin (Sedlec HJ-2 Borehole) links up bathymetrically with nearly adequate otolith assemblages in the southernmost Moravian part of the foredeep. Ten meso- and bathypelagic teleost species have been identified in the Vienna Basin for the first time. Geological analyses proved inversion processes of recurrent nature along old faults of the NW-SE direction in the Dyje (Thaya) Depression. In the early Badenian the Mikulov Gate resulted from the sagging block of the Waschberg Zone. This marine channel was relatively deep (> 200m, as indicated by otoliths) and in all probability flooded an entire front of the nappes in this area. 相似文献
13.
The dependence of stream depletion by seasonal pumping on various hydraulic characteristics and engineering factors 总被引:1,自引:2,他引:1
Compensation pumping is used to alleviate deficiencies in streamflow discharge during dry seasons. Short-term groundwater pumping can use aquifer storage instead of catchment-zone water until the drawdown reaches the edge of the stream. The capacitance is a complex, dimensionless parameter of an aquifer system that defines the delayed effect on streamflow when there is groundwater pumping. This parameter is a function of aquifer hydraulic characteristics, pumping time, and distance between the well and stream edge; the latter can involve stream leakance and vertical leakance of an associated aquitard. Three typical hydraulic cases of combined water systems (major catchment-zone wells close to the stream and compensation pumping wells) were classified depending on their capacitance structure (i.e. the relationship between surface water and groundwater): (1) perfect hydraulic connection between the stream and aquifer; (2) imperfect hydraulic connection between the stream and aquifer; and (3) essentially imperfect hydraulic connection between the stream and the underlying confined aquifer. The impact of various hydraulic characteristics and engineering factors on stream depletion was examined by conceptual and numerical modeling. To predict the suitability and efficiency of a combined water system application, regression tests were undertaken on unit stream depletion and capacitance, and power dependencies were defined. 相似文献
14.
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
15.
Pavel Koten Jiří Borovička Pavel Spurný Stephen Evans Rostislav Štork Andrew Elliott 《Earth, Moon, and Planets》2008,102(1-4):151-156
We carried out double station observations of the Leonid meteor shower outburst, which occurred in the morning hours of November
19, 2006. Using image-intensified cameras we recorded approximately 100 Leonid meteors. As predicted, the outburst was rich
especially in fainter meteors. The activity profile shows that the peak of the outburst occurred at 4:40 ± 0:05 UT. The maximum
reached flux was 0.03 meteoroids km−2 hod−1 for meteors brighter than +6.5 magnitude. 相似文献
16.
We evaluate the statistical properties of low-level jets (LLJs) observed by means of a network of Doppler sodars in the Moscow
region, Russia. Continuous long-term measurements of the echo-signal intensity and wind-velocity profiles were carried out
in July 2005 and in 2008–2010 synchronously in the centre of Moscow and at a rural site. The summertime nocturnal LLJs have
a very clear diurnal cycle and exhibit features predicted by the Blackadar mechanism. In contrast, the long-lasting wintertime
jets do not have any clear diurnal variability. The urban environment strongly influences LLJs in both seasons: above the
city LLJs are higher, weaker and observed more rarely than at the rural site. In very cold periods (air temperature below
−8°C) no LLJs were observed over the city, instead convection emerged in the urban boundary layer. The results are based on
observations made in July 2005, January and December 2009, and January 2011. 相似文献