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291.
Numerical analysis of the groundwater regime in the western Dead Sea escarpment, Israel + West Bank 总被引:2,自引:2,他引:0
Agnes Gräbe Tino Rödiger Karsten Rink Thomas Fischer Feng Sun Wenqing Wang Christian Siebert Olaf Kolditz 《Environmental Earth Sciences》2013,69(2):571-585
Water is scarce in the semi-arid to arid regions around the Dead Sea, where water supply mostly relies on restricted groundwater resources. Due to increasing population in this region, the regional aquifer system is exposed to additional stress. This results in the continuous decrease in water level of the adjacent Dead Sea. The interaction of an increasing demand for water due to population growth and the decrease of groundwater resources will intensify in the near future. Thus, the water supply situation could worsen significantly unless sustainable water resource management is conducted. In this study, we develop a regional groundwater flow model of the eastern and southern Judea Group Aquifer to investigate the groundwater regime in the western Dead Sea drainage basin of Israel and the West Bank. An extensive geological database was developed and consequently a high-resolution structural model was derived. This structural model was the basis for various groundwater flow scenarios. The objective was to capture the spatial heterogeneity of the aquifer system and to apply these results to the southern part of the study area, which has not been studied in detail until now. As a result we analyzed quantitatively the flow regime, the groundwater mass balance and the hydraulic characteristics (hydraulic conductivity and hydraulic head) of the cretaceous aquifer system and calibrated them with PEST. The calibrated groundwater flow model can be used for integrated groundwater water management purposes in the Dead Sea area, especially within the framework of the SUMAR-Project. 相似文献
292.
Mathieu Duval Christophe Falguères Jean-Jacques Bahain Rainer Grün Qingfeng Shao Maxime Aubert Jean-Michel Dolo Jordi Agustí Bienvenido Martínez-Navarro Paul Palmqvist Isidro Toro-Moyano 《Quaternary Research》2012,77(3):482-491
The combined U-series/electron spin resonance (ESR) dating method was applied to nine teeth from two Early Pleistocene archaeological sites located in the Orce area (Guadix-Baza Basin, Southern Spain): Fuente Nueva-3 (FN-3) and Barranco León (BL). The combination of biostratigraphy and magnetostratigraphy places both sites between the Olduvai and Jaramillo subchrons (1.78–1.07 Ma).Our results highlight the difficulty of dating such old sites and point out the limits of the combined U-series/ESR dating method based on the US model. We identified several sources of uncertainties that may lead to inaccurate age estimates. Seven samples could not be dated because the dental tissues had (230Th/234U) activity ratios higher than equilibrium, indicating that uranium had probably leached from these tissues. It was however possible to calculate numerical estimates for two of the teeth, both from FN-3. One yielded a Middle Pleistocene age that seems to be strongly underestimated; the other provided an age of 1.19 ± 0.21 Ma, in agreement with data obtained from independent methods. The latter result gives encouragement that there are samples that can be used for routine dating of old sites. 相似文献
293.
294.
Elisabeth Frot Bas van Wesemael Grégoire Vandenschrick Roland Souchez Albert Solé Benet 《水文研究》2007,21(3):359-368
Isotope signatures in precipitation from the Global Network for Isotopes in Precipitation around the Mediterranean basin and literature data are compared with isotopic data from a large karstic aquifer in southeast Spain to explain the origin and type of the precipitation events dominating recharge. Analysis of the deuterium excess d at the scale of the Mediterranean basin and at the regional scale allows us to understand the isotopic context of the study area: Campo de Dalias and the Sierra de Gador (Almería province). The origin of precipitation can be determined from its d value. The d value changes as a function of the initial evaporation condition. It depends on the relative humidity and temperature during the evaporation producing the water vapour of the clouds. The water vapour, which dominates the study area, is generated in two areas: the Atlantic Ocean (d = 10‰) and the western Mediterranean basin (d = 15‰). With increasing precipitation volume, the western Mediterranean character dominates. These heavier storms contribute mainly to recharge, as illustrated by the d value of 13·6‰ in deep groundwater of the Campo de Dalias. Weighted d values increase with the volume of precipitation, giving a significant relationship for the southern and eastern coasts of the Iberian Peninsula. This selectivity of d to monthly precipitation was used to estimate the return period of precipitation leading to aquifer recharge at 0·9–4·9 years. Moderate rainfall, which occurs more frequently, still represents ~60–90% of the total precipitation. One of the challenges to meet ever‐growing water demands is to increase recharge from moderate events yielding intermediate quantities per event, but forming the bulk of the annual precipitation. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
295.
Progressive deformation of a zone of magma transfer in a transpressional regime: The Variscan Mérens shear zone (Pyrenees, France) 总被引:1,自引:0,他引:1
The EW-striking Variscan Mérens shear zone (MSZ), located on the southern border of the Aston dome (Pyrenees), corresponds to variously mylonitized gneisses and plutonic rocks that are studied using the Anisotropy of Magnetic Susceptibility (AMS) technique. The plutonic rocks form EW-striking bands with, from south to north, gabbro-diorites, quartz diorites and granodiorites. The MSZ underwent a mylonitic deformation with an intensity progressively increasing from the mafic to the more differentiated rocks. The foliations are EW to NW–SE striking and subvertical. A first set of lineations shows a moderate WNW plunge, with a dextral reverse kinematics. More recent subvertical lineations correspond to an uplift of the northern compartment. To the east, the MSZ was cut by a N120°E-striking late shear band, separating the MSZ from the Quérigut pluton. The different stages of mylonitization relate to Late Variscan dextral transpression. This regime allowed the ascent of magmas along tension gashes in the middle crust. We interpret the MSZ as a zone of magma transfer, which fed a pluton now eroded that was similar to the Quérigut and Millas plutons located to the east. We propose a model of emplacement of these plutons by successive pulses of magmas along en-échelon transfer zones similar to the MSZ. 相似文献
296.
Evaluating Topological Queries in Linked Data Using DBpedia and GeoNames in Switzerland and Scotland
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This article explores the practicability and assesses the quality of searches for Wikipedia pages of topologically related administrative divisions in Switzerland and Scotland via Linked Data. To this end, the quality of searches in the English and German versions of DBpedia is compared, as is that of searches in GeoNames and DBpedia using DBpedia's links to GeoNames or a manually created list of links. In addition, the effects of updates to Swiss municipality borders in the English version of DBpedia on standard quality metrics are studied. It turns out that live searches are practicable with acceptable performance, but that the quality of searches in terms of recall and precision is acceptable only if DBpedia is queried via GeoNames and DBpedia's links to GeoNames are replaced by manually created links. Searches for Scottish unitary authority wards perform poorly for all approaches investigated. Recall and precision are strongly influenced by changes in municipality borders, with a relatively long latency suggesting that, at least in some cases, administrative changes propagate slowly into DBpedia. These results have important implications for those seeking to use location as a means to link data. 相似文献
297.
Youness Dehbi Fabian Hadiji Gerhard Gröger Kristian Kersting Lutz Plümer 《Transactions in GIS》2017,21(1):134-150
The automatic interpretation of 3D point clouds for building reconstruction is a challenging task. The interpretation process requires highly structured models representing semantics. Formal grammars can describe structures as well as the parameters of buildings and their parts. We propose a novel approach for the automatic learning of weighted attributed context‐free grammar rules for 3D building reconstruction, supporting the laborious manual design of rules. We separate structure from parameter learning. Specific Support Vector Machines (SVMs) are used to generate a weighted context‐free grammar and predict structured outputs such as parse trees. The grammar is extended by parameters and constraints, which are learned based on a statistical relational learning method using Markov Logic Networks (MLNs). MLNs enforce the topological and geometric constraints. MLNs address uncertainty explicitly and provide probabilistic inference. They are able to deal with partial observations caused by occlusions. Uncertain projective geometry is used to deal with the uncertainty of the observations. Learning is based on a large building database covering different building styles and façade structures. In particular, a treebank that has been derived from the database is employed for structure learning. 相似文献
298.
Katarina Pavlek Filip Bišćević Petra Furčić Ana Grđan Vesna Gugić Nino Malešić 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2017,117(1):22-35
Wildfires are an important factor of landscape dynamics in fire-prone environments of the world. In the Mediterranean, one of the most fire-susceptible environments globally, between 45,000 and 50,000 wildfires are recorded every year, causing disturbances in forest and grassland ecosystems. As a Mediterranean country, Croatia faces these problems, averaging over 1000 registered wildfires annually, with the coastal areas dominated by forest fires and continental Croatia by fires on agricultural lands. This research combines various landscape and socio-economic factors in the analysis of fire occurrence in Croatia’s southernmost region of Dalmatia. Around 275 of the largest fires (encompassing 98% of the total burnt area) registered in 2013 were investigated using OLS, and different spatial indices were employed to analyse regional variability in fire distribution. The results revealed that areas more prone to fires are the northern inland areas of Dalmatia and its entire coastal zone. Altitude and vegetation type demonstrated a correlation with fire occurrence, but an increase in population in the study area was also correlated with wildfire occurrence. Regarding vegetation, the grasslands and Mediterranean shrubland (maquis) were found to be the most fire-prone vegetation types in the study region, the distribution of which can be linked to different socio-economic and demographic processes occurring in the Eastern Adriatic. 相似文献
299.
We present a geomorphologic analysis of an east‐west transect located east of the southern Andes of Argentina (~37°S). We observe a succession of zones that underwent erosion and deposition during the Pleistocene. If the proximal Andean foothills are incised, a proximal depozone receives sediments feeding the megafan of the Rio Colorado on the Chadileuvú plain. More distally, the abandoned palaeo‐valleys and bending of the valley floors reflect a localized uplift. Further to the east, another depozone corresponds to the Pampa Deprimida lowland. This pattern is consistent with the presence of a classical flexural geometry of the lithosphere. The distal uplift of the foreland corresponds in terms of location, length (150 km) and amplitude (240 m) to the Andean forebulge modelled by a geophysical approach. In this study, we identify the morphological imprint of this bulge and show its effect on the fluvial activity. 相似文献
300.
Daily stream temperatures are needed in a number of analyses. Such analyses might focus on aquatic organisms or industrial activities. To protect aquatic systems, industrial activities, for example, water withdrawals or discharges, are sometimes restricted. To evaluate where new industrial settings should be placed or if climate change will affect already existing industrial settings, the simulation of stream temperature is needed. Stream temperature models with weekly or monthly time scale might not be sufficient for this kind of analysis. Different regression models to simulate daily stream temperature for the river Elbe (Germany) are developed and their performance is estimated. For the calibration period the Nash–Sutcliffe coefficient (NSC) for the simplest model is 0·97, and the root mean squared error (RMSE) is 1·48 °C. For the most sophisticated model the NSC also is 0·97. However, the RMSE is 1·32 °C. For the validation period the NSC for the simplest model is 0·96, and the RMSE is 1·45 °C. The NSC for the most sophisticated model is 0·97, and the RMSE is 1·25 °C. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献