Modeling coupled unsaturated and saturated nitrate distribution of the aquifer Westliches Leibnitzer Feld, Austria     

Gernot Klammler  Hans Kupfersberger  Gerhard Rock  Johann Fank 《Environmental Earth Sciences》2013,69(2):663-678

The aquifer Westliches Leibnitzer Feld, Austria, is a significant resource for regional and supraregional drinking water supply for more than 100,000 inhabitants, but the region also provides excellent agricultural conditions. This dual use implicates conflicts (e.g., non-point source groundwater pollution by nitrogen leaching), which have to be harmonized for a sustainable coexistence. At the aquifer scale, numerical models are state-of-the-art tools to simulate the behavior of groundwater quantity and quality and serve as decision support system for implementing groundwater protecting measures. While fully and iteratively coupled simulation models consider feedback between the saturated and unsaturated zone, sandy soil conditions and groundwater depths beneath the root zone allow the use of a unidirectional sequential coupling of the unsaturated water flow and nitrate transport model SIMWASER/STOTRASIM with FEFLOW for the investigation area. Considering separated inputs of water and nitrogen into groundwater out of surface water bodies, agricultural, residential and forested areas, first simulation results match observed groundwater tables, but underestimate nitrate concentrations in general. Thus, multiple scenarios assuming higher nitrogen inputs at the surface are simulated to converge with measured nitrate concentrations. Preliminary results indicate that N-input into the groundwater is strongly dominated by contributions of agricultural land.  相似文献   

EPC: Matlab software to estimate Euler pole parameters   总被引：1，自引：1，他引：0  

Mohammad Ali Goudarzi  Marc Cocard  Rock Santerre 《GPS Solutions》2014,18(1):153-162

The estimation of Euler pole parameters has always been an important issue in global tectonics and geodynamics studies. In addition, the increasing number of permanent GPS stations and the ease of access to their data, along with advances in computers, promise new methods and tools for the estimation and the quantitative analysis of Euler pole parameters. Therefore, we developed the Euler pole calculator software using a set of mathematical algorithms based on the model of tectonic plate motion on a spherical surface. The software is able to calculate the expected velocities for any points located on the earth’s surface given the relevant Euler pole parameters and to estimate the Euler pole parameters given the observed velocities of a set of sites located on the same tectonic plate. Mathematical algorithms and functions of the software are explained in detail.  相似文献   

Improving the representation of major landforms in analytical relief shading     

Brooke E. Marston  Bernhard Jenny 《International journal of geographical information science》2013,27(7):1144-1165

Relief shading is the most common type of cartographic relief representation for print and digital maps. Manual relief shading results in informative and visually pleasing representations of terrain, but it is time consuming and expensive to produce. Current analytical relief shading can be created quickly, but the resulting maps are not as aesthetically appealing and do not show landscape features in an explicit manner. This article introduces an automated digital method that produces shaded relief with locally adjusted illumination directions to simulate the techniques and cartographic principles of manual relief shading. Ridgelines and valley lines are derived from a digital terrain model, vectorized, and used in a diffusion curve algorithm. A graph analysis generalizes the lines before using them for diffusion curve shading. The direction of illumination is adjusted based on the spatial orientation of ridgelines and valley lines. The diffusion curve shading is combined with standard analytical relief shading to create a final diffusion relief shading image. Similar to manual relief shading, major landforms and the structure of the terrain are more clearly shown in the diffusion relief shading. The presented method best highlights major landforms in terrain characterized by sharp, clearly defined ridges and valleys.  相似文献   

Surface and subsurface water contributions to streamflow from a mesoscale watershed in complex mountain terrain          下载免费PDF全文

Qinghuan Zhang  John F. Knowles  Rebecca T. Barnes  Rory M. Cowie  Nathan Rock  Mark W. Williams 《水文研究》2018,32(7):954-967

An understanding of surface and subsurface water contributions to streamflow is essential for accurate predictions of water supply from mountain watersheds that often serve as water towers for downstream communities. As such, this study used the end‐member mixing analysis technique to investigate source water contributions and hydrologic flow paths of the 264 km² Boulder Creek Watershed, which drains the Colorado Front Range, USA. Four conservative hydrochemical tracers were used to describe this watershed as a 3 end‐member system, and tracer concentration reconstruction suggested that the application of end‐member mixing analysis was robust. On average from 2009 to 2011, snowmelt and rainwater from the subalpine zone and groundwater sampled from the upper montane zone contributed 54%, 22%, and 24% of the annual streamflow, respectively. These values demonstrate increased rainwater and decreased snow water contributions to streamflow relative to area‐weighted mean values derived from previous work at the headwater scale. Young water (2.3 ± 0.8 months) fractions of streamflow decreased from 18–22% in the alpine catchment to 8–10% in the lower elevation catchments and the watershed outlet with implications for subsurface storage and hydrological connectivity. These results contribute to a process‐based understanding of the seasonal source water composition of a mesoscale watershed that can be used to extrapolate headwater streamflow generation predictions to larger spatial scales.  相似文献   

Hässeldala – a key site for Last Termination climate events in northern Europe     

Barbara Wohlfarth  Francesco Muschitiello  Sarah L. Greenwood  August Andersson  Malin Kylander  Rienk H. Smittenberg  Margret Steinthorsdottir  Jenny Watson  Nicola J. Whitehouse 《Boreas: An International Journal of Quaternary Research》2017,46(2):143-161

The Last Termination (19 000–11 000 a BP) with its rapid and distinct climate shifts provides a perfect laboratory to study the nature and regional impact of climate variability. The sedimentary succession from the ancient lake at Hässeldala Port in southern Sweden with its distinct Lateglacial/early Holocene stratigraphy (>14.1–9.5 cal. ka BP) is one of the few chronologically well‐constrained, multi‐proxy sites in Europe that capture a variety of local and regional climatic and environmental signals. Here we present Hässeldala's multi‐proxy records (lithology, geochemistry, pollen, diatoms, chironomids, biomarkers, hydrogen isotopes) in a refined age model and place the observed changes in lake status, catchment vegetation, summer temperatures and hydroclimate in a wider regional context. Reconstructed mean July temperatures increased between c. 14.1 and c. 13.1 cal. ka BP and subsequently declined. This latter cooling coincided with drier hydroclimatic conditions that were probably associated with a freshening of the Nordic Seas and started a few hundred years before the onset of Greenland Stadial 1 (c. 12.9 cal. ka BP). Our proxies suggest a further shift towards colder and drier conditions as late as c. 12.7 cal. ka BP, which was followed by the establishment of a stadial climate regime (c. 12.5–11.8 cal. ka BP). The onset of warmer and wetter conditions preceded the Holocene warming over Greenland by c. 200 years. Hässeldala's proxies thus highlight the complexity of environmental and hydrological responses across abrupt climate transitions in northern Europe.  相似文献   

矿物收藏漫谈(五) 这些矿物杂志和书籍,实在精彩     

Rock H.Currire  易经  胡能勇 《国土资源导刊(湖南)》2010,7(5)

<正>上期中提到了一些关于矿物标本的书籍,这里再列出几本实在精彩的有关矿物收藏知识的书籍和杂志,因为他们实在是精彩。  相似文献   

矿物收藏漫谈(四)去文献里收藏你需要的矿业知识     

易经 《国土资源导刊(湖南)》2010,7(4)

正尽可能多地去参观这些收藏吧!由私人捐赠的收藏常常是大型机构收藏的重要组成部分。大多数收藏者都热衷于炫耀自己的藏品。如果你遇见一位拥有上好藏品的人,你可以这样来进行自我  相似文献   

矿物收藏漫谈(八) 野外采集让收藏者多才多艺     

易经 《国土资源导刊(湖南)》2010,7(8):84-85

<正>上期对一般收藏和特色收藏进行了初步介绍,这里我们来了解一些常见的特色收藏形式,首先就是野外采集。听起来似乎很美妙,不过,这只是它的一个方面而已,也许,深入其中后,你能够感受到它犹如火焰般炽人的另一面。因为我首先要告诫大家的就是,如果不是狂热地热爱并深刻了解它,不要轻易辞掉你的工作,否则你很可能会因为搬不动太多的石头,而成为大山里的流浪者。  相似文献   

Present-Day 3D Velocity Field of Eastern North America Based on Continuous GPS Observations     

Mohammad Ali Goudarzi  Marc Cocard  Rock Santerre 《Pure and Applied Geophysics》2016,173(7):2387-2412

  相似文献   

Improving vertical GPS precision with a GPS-over-fiber architecture and real-time relative delay calibration   总被引：2，自引：0，他引：2  

Daniel Macias-Valadez  Rock Santerre  Sophie Larochelle  René Landry Jr. 《GPS Solutions》2012,16(4):449-462

A limitation of GPS positioning is that the vertical component is generally two to three times less precise than the horizontal components. In a previous work by R. Santerre of Laval University and G. Beutler of University of Bern, it was shown in simulations that it is possible to improve the GPS vertical positioning precision by using a multi-antenna GPS receiver and a precise calibration technique of the relative hardware delay between the antennas and the receiver. However, no actual implementation of the system was done to prove the concept until now. A new multi-antenna, GPS-over-fiber architecture with real-time delay monitoring, designed and implemented to improve the vertical precision is presented. The improvement in vertical precision arises from the elimination of the relative receiver clock error in single difference, between antennas, and the precision real-time calibration of the relative hardware delay. Experiments were conducted with a zero baseline and a short baseline configuration. The results show, as expected by the theory and the simulations, a two to three times improvement in the precision of the vertical component such that it reached the same level of performance as the horizontal components. These promising results will enable the use of this type of configuration in several applications where the same precision in all 3D components is essential and could not be achieved before with standard GPS positioning techniques.  相似文献