Investigating hydrological drivers of nitrate export dynamics in two agricultural catchments in Germany using high-frequency data series   总被引：1，自引：1，他引：0  

Marc Schwientek  Karsten Osenbrück  Matthias Fleischer 《Environmental Earth Sciences》2013,69(2):381-393

In this study near-continuous time series of nitrate, electrical conductivity, and discharge were used to identify the dominating hydrological mechanisms that control nitrate export dynamics in two agricultural catchments. The main goal was to assess relationships between contrasting event based as well as long-term nitrate transport behaviour and catchment hydrology. Data records were obtained from online probes that allow field based high-frequency analyses over long time periods. The catchments of the Ammer River (southwestern Germany) and the Weida River (eastern Germany) are similar with respect to size (~100 km²), morphology, and climate and are dominated by agricultural use. Main differences are the stronger urbanization and the occurrence of karstic rocks in the Ammer catchment. Nitrate concentrations are high in water of both streams and range mostly between 20 and 50 mg l^?1. Nitrate export in the Ammer catchment is dominated by baseflow and a minor second, diluting runoff component generated in urbanized areas. In contrast, nitrate dynamics of the Weida catchment is governed by the interplay of at least three runoff components, while the largest amount of nitrate is mobilized intermittently by a delayed fast component generated in the catchment’s soils during wet conditions. These interpretations, derived with one online probe at the outlet of each catchment, are well in line with the former modeling results. This study shows that high-resolution data obtained by online techniques offers a large potential to improve the conceptualization of dominating flow and transport processes at catchment scales at relatively low costs and effort.  相似文献   

A data exploration framework for validation and setup of hydrological models   总被引：5，自引：5，他引：0  

Karsten Rink  Thomas Fischer  Benny Selle  Olaf Kolditz 《Environmental Earth Sciences》2013,69(2):469-477

Over the course of hydrological research projects often a large number of heterogeneous data sets are acquired from sources as diverse as boreholes, gauging stations or satellite imagery. This data then need to be integrated into models for the simulation of hydrological processes. We propose a framework for exploration of geoscientific data and visually guided preparation of such models. Data sets from a large number of sources can be imported, combined and validated to avoid potential problems due to artefacts or inconsistencies between data sets in a subsequent simulation. Boundary conditions and domain discretisations for surface and subsurface models can be created and tested regarding criteria indicating possible numerical instabilities. All data sets including simulation results can be integrated into a user-controlled 3D scene and aspects of the data can be enhanced using a number of established visualisation techniques including thresholding and user-defined transfer functions. We present the application of this framework for the preparation of a model for simulation of groundwater flow in a river catchment in southwest Germany investigated in the scope of the WESS project.  相似文献   

Hydrodynamics and sediment dynamics in the German Bight. A focus on observations and numerical modelling in the East Frisian Wadden Sea     

Joanna Staneva  Emil V. Stanev  Jörg-Olaf Wolff  Thomas H. Badewien  Rainer Reuter  Burghard Flemming  Alexander Bartholomä  Karsten Bolding 《Continental Shelf Research》2009

This work deals with analysis of hydrographic observations and results of numerical simulations. The data base includes acoustic Doppler current profilers (ADCP) observations, continuous measurements on data stations and satellite data originating from the medium resolution imaging spectrometer (MERIS) onboard the European Space Agency (ESA) satellite ENVISAT with a spatial resolution of 300 m. Numerical simulations use nested models with horizontal resolutions ranging from 1 km in the German Bight to 200 m in the East Frisian Wadden Sea coupled with a suspended matter transport model. Modern satellite observations have now a comparable horizontal resolution with high-resolution numerical model of the entire area of the East Frisian Wadden Sea allowing to describe and validate new and so far unknown patterns of sediment distribution. The two data sets are consistent and reveal an oscillatory behaviour of sediment pools to the north of the back-barrier basins and clear propagation patterns of tidally driven suspended particulate matter outflow into the North Sea. The good agreement between observations and simulations is convincing evidence that the model simulates the basic dynamics and sediment transport processes, which motivates its further use in hindcasting, as well as in the initial steps towards forecasting circulation and sediment dynamics in the coastal zone.  相似文献   

蒙古古生代地层研究的新进展   总被引：1，自引：0，他引：1  

王成源  Weddige Karsten  Minjin Chuluun 《吉林大学学报(地球科学版)》2006,36(5):723-735

蒙古国古生代地层的研究以往主要侧重底栖大化石的研究, 很多地层的时代划分、归属问题不能得到很好的解决,底栖化石的地方性很强,不能与国际直接对比。 牙形刺是古生代地层的主导化石, 很多古生代地层问题都可以用牙形刺解决并进行可靠的洲际间对比。2001年笔者在蒙古南戈壁采集了158个样品, 经分析发现了大量牙形刺标本, 解决了很多蒙古的重大地层问题。Arynshand组应当归入下石炭统, 泥盆-石炭系界线在Arynshand组之下, 而不是在此组的内部。Mushgai地区Bayan-Khoshuu Ruins剖面的Mandalovoo组Gavuu 段的上部应属早泥盆世早期, 而不是以前所确定的早志留世, 称为奥咯诺伍德组（Olonovoot Formation）;Gavuu段的下部仍归早志留世。Mandalovoo组应提升为Mandalovoo群;Gavuu段应提升为Gavuu组。南戈壁Shine Jinst地区Tsakhir剖面Tsagaanbulag组的时代是早泥盆世洛霍考夫期, 而不是中晚志留世,Ulaan-Shand剖面Tsagaanbulag组的时代也是早泥盆世洛霍考夫期。Chuluun组的时代为早泥盆世晚埃姆斯期。Tsagaankhaalga组的时代为早艾菲尔期。Indert组为早石炭世。蒙古古生代海相地层大部分是浅水相地层, 并可能存在5个间断：志留系的文洛克统和罗德洛统的下部,下泥盆统布拉格阶的一部分,中泥盆统艾菲尔阶上部,泥盆-石炭系界线地层。蒙古国南部和中部很可能缺失上二叠统的海相沉积。  相似文献   

Microbiological-Immunological Rapid Method to Detect Legionellaceae in Water     

I. Hübner  U. Obst  I. Steinmetz  D. Bitter-Suermann 《洁净——土壤、空气、水》1992,20(4):205-207

Specific and sensitive immunological assays for the detection of bacteria are able to substitute the conventional microbiological control of drinking water. In cooperation with the Medical University of Hannover immunological assays were developed based on monoclonal antibodies against specific bacterial antigens. The immunological methods were combined with a shortened microbiological pre-enrichment, because the sensitivity of the immunoassays was too low to fulfill the requirements of the drinking water ordinance. Legionella colonies grown on a solid selective medium are detectable within 2 h only by an immunological dot-blot method using a monoclonal antibody against the legionella heat shock protein. The method proved its validity in first test series at the municipal water works Mainz and will be screened intensively in further studies. The intent is to find a standardization analogous to that of the immunological detection of enterobacteria [1].  相似文献   

The development of a non-linear autoregressive model with exogenous input (NARX) to model climate-water clarity relationships: reconstructing a historical water clarity index for the coastal waters of the southeastern USA     

Lee  Cameron C.  Sheridan  Scott C.  Barnes  Brian B.  Hu  Chuanmin  Pirhalla  Douglas E.  Ransibrahmanakul  Varis  Shein  Karsten 《Theoretical and Applied Climatology》2017,130(1-2):557-569

Theoretical and Applied Climatology - The coastal waters of the southeastern USA contain important protected habitats and natural resources that are vulnerable to climate variability and singular...  相似文献   

Electrical anisotropy and conductivity distribution functions of fractal random networks and of the crust: the scale effect of connectivity     

Karsten Bahr 《Geophysical Journal International》1997,130(3):649-660

All explanations of the high-conductivity layers (HCL) found by magnetotellurics in the middle or lower crust incorporate a mixture of a low-conductivity rock matrix and a highly conductive phase, for example graphite or saline fluids. In most cases the bulk conductivity of the mixture does not depend on the conductivity of the rock matrix but rather (1) on the amount of high-conductivity material and, in particular, (2) on its geometry. The latter is quantitatively described by the parameter 'electrical connectivity'. Decomposition of the observed bulk conductivity of the mixture into these two parameters results in an ill-posed problem. Even if anisotropy occurs in the HCL, three output parameters (highly conductive phase fraction, connectivity with respect to the X direction, connectivity with respect to the Y direction) have to be estimated from the two bulk conductivities of the anisotropic HCL. The additional information required for solving this problem is provided if instead of single-site data the conductivities from many field sites are evaluated: a sample distribution of the conductivity can then be obtained. Ensembles of random networks are used to create theoretical distribution functions which match the empirical distribution functions to some extent. The use of random resistor networks is discussed in the context of other established techniques for the treatment of two-phase systems, such as percolation theory and the renormalization group approach. Models of embedded networks explain the discrepancy between 'small' anisotropy (2-3) on the laboratory scale and large anisotropy (10-100) found in electromagnetic field surveys encompassing volumes of several cubic kilometres. Strong anisotropy can indicate low electrical connectivity, and a possible explanation is that a network stays close to the percolation threshold.  相似文献   

Gewässergütebewertung und Bewertung von Abwasserfahnen in Rhein und Main auf der Basis mikrobieller Enzymaktivitäten     

A. Weßler  K. Dmgen  R. Hryk  U. Obst 《洁净——土壤、空气、水》1997,25(1):17-26

Quality Mapping of Surface Water and Assessment of Treated and Untreated Waste-water Inputs into the Rhine and Main River Based on Microbial Enzyme Activities Microbial enzyme activities are used for an extension of the traditional quality mapping of surface water. In the following study, the enzymatic parameters were proved and validated on samples from various creeks and rivers in Baden-Württemberg and on samples gathered from the Rhine and Main Rivers (Germany). The test parameters should also be used for the control and the preservation of the capacity of the biological self-purification, which is the only natural and essential process in drinking-water conditioning of surface water. Main subject of the surveys was the development of criteria for an assessment of the measured enzymatical inhibition effects. Therefore, classes of inhibition and indices of inhibition are defined.  相似文献   

Recovery of Danish Coastal Ecosystems After Reductions in Nutrient Loading: A Holistic Ecosystem Approach     

Bo Riemann  Jacob Carstensen  Karsten Dahl  Henrik Fossing  Jens W. Hansen  Hans H. Jakobsen  Alf B. Josefson  Dorte Krause-Jensen  Stiig Markager  Peter A. Stæhr  Karen Timmermann  Jørgen Windolf  Jesper H. Andersen 《Estuaries and Coasts》2016,39(1):82-97

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The end of trend estimation for extreme floods under climate change?          下载免费PDF全文

Karsten Schulz  Matthias Bernhardt 《水文研究》2016,30(11):1804-1808

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