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Malgorzata Stramska 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(9):1459-1470
Satellite remote sensing offers new means of quantifying particulate organic carbon, POC, concentration over large oceanic areas. From SeaWiFS ocean color, we derived 10-year data of POC concentration in the surface waters of the global ocean. The 10-year time series of the global and basin scale average surface POC concentration do not display any significant long-term trends. The annual mean surface POC concentration and its seasonal amplitude are highest in the North Atlantic and lowest in the South Pacific, when compared to other ocean basins. POC anomalies in the North Atlantic, North Pacific, and global concentrations seem to be inversely correlated with El Niño index, but longer time series are needed to confirm this relationship. Quantitative estimates of POC reservoir in the oceanic surface layer depend on the choice of what should represent this layer. Global average POC biomass is 1.34 g m?2 if integrated over one optical depth, 3.62 g m?2 if integrated over mixed layer depth, and up to 6.41 g m?2 if integrated over 200-m layer depth (when assumed POC concentration below MLD is 20 mg m?3). The global estimate of total POC reservoir in the surface 200-m layer of the ocean is 228.61×1013 g. We expect that future estimates of POC reservoir may be even larger, when more precise calculations account for deep-water organic-matter maxima in oligotrophic regions, and POC biomass located just below the seasonal mixed layer in spring and summer in the temperate regions. 相似文献
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Malgorzata Labus 《Environmental Geology》2008,54(2):283-289
The scope of the paper is an attempt at the identification of the weathering-resistance classes within clastic rocks by means
of analysis of capillary pressure saturation curves. The porosimetric parameters corresponding to the cementing character
and the grains’ mineralogical content are very important features of stone building materials, because of the weathering processes.
The analysed rocks were Polish sandstones and muddy sandstones used for building purposes, collected from different geological
units of Poland (i.e. Sudety Mts. Carpathian Mts. and Holy Cross Mts.) The results indicate the usefulness of sandstone materials
for building purposes. They could also be used in conservation procedures and for the reconstruction of existing buildings
and monuments. Basing on the parameterisation, with the van Genuchten function, of cumulative capillary pressure saturation
curves, it was possible to distinguish four groups of the sampled rocks. The lithological features and weathering sustainability
within the groups are quite uniform, what allow identifying the weathering resistance classes. Taking into account the complicated
nature of all the factors influencing weathering processes, it is supposed that the presented parameterisation could be a
useful tool for weathering-resistance classification of clastic rocks. The classification could be useful in building industry
and in conservation of historical stone monuments. 相似文献
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Bioremediation is intensively studied today as a treatment method for soil contaminated with chlorinated pesticides, chemicals counted among persistent organic pollutants. In the presented work, results of desorption kinetics study using consecutive Tenax TA solid phase extraction (SPE) were tested as predictors of 3‐wk anaerobic soil bioremediation effectiveness for chlorinated pesticides γ‐HCH, DDT, and methoxychlor. Field‐contaminated samples were used in these experiments, and conditions of bioremediation tests were based on previous research. Amounts of pesticides removed during bioremediation (43–98% of initial concentrations) were in most cases much larger (average ratio 1.37) than rapidly desorbing fractions estimated in SPE using two‐compartment model of desorption kinetics. The scatter of results was also considerable (standard deviation 0.45). However, there was a statistically significant correlation between amounts removed and rapidly desorbing fractions (R2 = 0.64), indicating a relationship between degradability and desorbability. Nonetheless, determination of rapidly desorbing fractions was considered rather a poor indicator of soil bioremediation efficiency for chlorinated pesticides. The total amounts of pesticides desorbed by Tenax in 72 h performed better in this respect (R2 = 0.73, fraction removed/desorbed = 1.10 ± 0.20, average ± standard deviation). Disappearance of DDT during bioremediation was accompanied by DDD formation but this was considerably lower than results expected from stoichiometry. 相似文献
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Witold RECZYNSKI Malgorzata JAKUBOWSKA Janusz GOLAS Andrew PARKER Barbara KUBICA 《国际泥沙研究》2010,25(1):28-38
Sediments samples of the Dobczyce Reservoir(South Poland) were taken in three successive years(2004-06) at 17 points,analyzed for 12 elements by atomic absorption spectrometry.Substantial variations in elemental composition due to hydrological and environmental reasons were found.The use of statistical and chemometric tools enabled objective and effective analysis of the data obtained,both in case of long term observations as well as in terms of interpretation of incidental changes in metal concentrations.T... 相似文献
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Continental hydrological loading by land water, snow and ice is a process that is important for the full understanding of the excitation of polar motion. In this study, we compute different estimations of hydrological excitation functions of polar motion (as hydrological angular momentum, HAM) using various variables from the Global Land Data Assimilation System (GLDAS) models of the land-based hydrosphere. The main aim of this study is to show the influence of variables from different hydrological processes including evapotranspiration, runoff, snowmelt and soil moisture, on polar motion excitations at annual and short-term timescales. Hydrological excitation functions of polar motion are determined using selected variables of these GLDAS realizations. Furthermore, we use time-variable gravity field solutions from the Gravity Recovery and Climate Experiment (GRACE) to determine the hydrological mass effects on polar motion excitation. We first conduct an intercomparison of the maps of variations of regional hydrological excitation functions, timing and phase diagrams of different regional and global HAMs. Next, we estimate the hydrological signal in geodetically observed polar motion excitation as a residual by subtracting the contributions of atmospheric angular momentum and oceanic angular momentum. Finally, the hydrological excitations are compared with those hydrological signals determined from residuals of the observed polar motion excitation series. The results will help us understand the relative importance of polar motion excitation within the individual hydrological processes, based on hydrological modeling. This method will allow us to estimate how well the polar motion excitation budget in the seasonal and inter-annual spectral ranges can be closed. 相似文献
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We consider flow and upscaling of flow properties from pore scale to Darcy scale, when the pore-scale geometry is changing. The idea is to avoid having to solve for the pore evolution at the pore scale, because this results in unmanageable complexity. We propose to use stochastic modeling to parametrize plausible modifications of the pore geometry and to construct distributions of permeability parametrized by Darcy-scale variables. To localize the effects of, e.g., clogging, we introduce an intermediate scale of pore-network models. We use local Stokes solvers to calibrate the throat permeability. 相似文献
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In this paper we carry out numerical analysis for a family of simplified gas transport models with hydrate formation and dissociation in subsurface, in equilibrium and non-equilibrium conditions. These models are adequate for simulation of hydrate phase change at basin and at shorter time scales, but the analysis does not account directly for the related effects of evolving hydraulic properties. To our knowledge this is the first analysis of such a model. It is carried out for the transport steps while keeping the pressure solution fixed. We frame the transport model as conservation law with a non-smooth space-dependent flux function; the kinetic model approximates this equilibrium. We prove weak stability of the upwind scheme applied to the regularized conservation law. We illustrate the model, confirm convergence with numerical simulations, and illustrate its use for some relevant equilibrium and non-equilibrium scenarios.
相似文献19.
The paper is based on recent climate simulations provided by the leading world climate centres and available through the Data
Distribution Centre of the Intergovernmental Panel on Climate Change. Seven models have been considered. Three experiments:
control, and two integrations for different greenhouse gases emission scenarios have been analysed. Assessments have been
made for the European window defined as 5–40° E, 40–60° N. The paper presents some selected results for the air surface temperature
and precipitation. This is not a study on evaluation of models, detailed intercomparisons between models can be found in other
works (e.g., Barnett, 1999; Boer and Lambert, 2000; Lambert and Boer, 2001), as well as on Internet (e.g., a web-site of the
Program for Climate Model Diagnosis and Intercomparison1). The intention of the authors was to show examples of analyses made specifically for the Central European region. For the
reason of technical limitations of the paper only some results can be presented.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献