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121.
Development of a 3D groundwater model based on scarce data: the Wadi Kafrein catchment/Jordan 总被引:2,自引:2,他引:0
Yajie Wu Wenqing Wang Mathias Toll William Alkhoury Martin Sauter Olaf Kolditz 《Environmental Earth Sciences》2011,64(3):771-785
In this work, a 3D groundwater flow model integrating all important geological features of the hydrogeological system is developed
to investigate hydrological processes in the Wadi Kafrein area of Jordan. A large amount of available geological and hydrological
data is integrated to construct a 3D groundwater flow model for the Wadi Kafrein area. Using the newly developed mapping approach,
the translation of the highly detailed geological formations to an unstructured finite element grids, can be accomplished
with high precision. The existing data set for model calibration is scarce, which is a typical situation for many hydrogeological
case studies. At first, the steady state calibration of the groundwater model is carried out based on the observation wells.
Then, the time and space-dependent recharge from precipitation are applied at the top surface of the finite element model.
The transient simulation is conducted during the period of 1996–2008 considering the abstraction rates of the production wells
and discharge of the springs. The calculated water levels are close to the observed values. The difference is partly caused
by return flows from irrigation and the groundwater inflow from the adjacent aquifers which are not taken into consideration
so far. Since the Wadi Kafrein area is an important agricultural area in the semiarid region of the Lower Jordan Valley, the
model developed in this study can be regarded as a useful tool for analyzing the hydrological processes and improving groundwater
management practices elsewhere affected by similar geological and hydrogeological conditions. 相似文献
122.
The Salmon industry in Norway includes three sectors, namely sea and river fishing for wild salmon, and salmon farming, or aquaculture. The three sectors provide different social, economic and cultural benefits to society, but also face many problems and challenges. They have different interests, practices, traditions and audiences, and are also administered by different authorities and regulated under varying management regimes and legislations. On the one hand, they complement each other in terms of product supply, employment creation and income; on the other hand, they face conflicts over management objectives and strategies. This paper provides an overview of the salmon sectors associated with their status, challenges and management regimes. It further analyzes their interests and conflicts over economic contribution and management. Finally, some potential solutions are suggested in an attempt to solve these conflicts. 相似文献
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125.
A stratigraphic analysis of late Palaeocene sands of the Søgne Basin and the western part of the Norwegian–Danish Basin shows that the sand bodies are of differenct ages. The geographic distribution of the sand deposits shows that they are related to underlying Mesozoic structures suggesting a controlling effect of Tertiary tectonics on the deposition of sand during the late Palaeocene. However, the structural setting of various sand bodies varies from reactivation of older faults and reactivation of salt structures. The local character of the structures active during the late Palaeocene introduces minor depressions with no lateral connection. The sand bodies, which are interpreted as having been deposited in these depressions, are thus in general separate bodies with no lateral connection. The Fennoscandian shield and eroded Mesozoic sediments along the Fennoscandian Border Zone are suggested as source area for the late Palaeocene sand deposits. 相似文献
126.
We studied the problematic of uncertainties in the diffuse gamma radiation apparent in stacking analysis of EGRET data at low Galactic latitudes. Subsequently, we co-added maps of counts, exposure and diffuse background, and residuals, in varying numbers for different sub-categories of putatively and known source populations (like PSRs). Finally we tested for gamma-ray excess emission in those maps and attempt to quantify the systematic biases in such approach. Such kind of an analysis will help the classification processes of sources and source populations in the GLAST era. 相似文献
127.
High‐resolution loss‐on‐ignition analyses of lacustrine sediment cores from both proglacial and non‐glacial lakes in southern Norway have revealed a specific pattern characterised by a significant, two‐peaked reduction of the loss‐on‐ignition values in the basal half of the cores. In non‐glacier‐fed lakes, the loss‐on‐ignition variations are interpreted to reflect mainly lake productivity and hence variability in surface summer air temperature. Sediments deposited in proglacial lakes, however, reflect mainly the glacier activity in the lake catchment. Bulk AMS radiocarbon dates from the core sequences and the loss‐on‐ignition curve pattern suggest that this event correlates with the ‘8200 cal. yr BP event’ recorded in the GRIP and GISP2 Greenland ice‐cores, termed the Finse event in southern Norway. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
128.
Olaf Juschus Maksim Pavlov Georg Schwamborn Frank Preusser Grigory Fedorov Martin Melles 《Quaternary Research》2011,76(3):441-451
Lake El'gygytgyn is situated in a 3.6 Ma old impact crater in northeastern Siberia. Presented here is a reconstruction of the Quaternary lake-level history as derived from sediment cores from the southern lake shelf. There, a cliff-like bench 10 m below the modern water level has been investigated. Deep-water sediments on the shelf indicate high lake levels during a warm Mid-Pleistocene period. One period with low lake level prior to Marine Oxygen Isotope Stage (MIS) 3 has been identified, followed by a period of high lake level (10 m above present). In the course of MIS 2 the lake level dropped to − 10 m. At the end of MIS 2 the bench was formed and coarse beach sedimentation occurred. Subsequently, the lake level rose rapidly to the Holocene level. Changes in water level are likely linked to climate variability. During relatively temperate periods the lake becomes free of ice in summer. Strong wave actions transport sediment parallel to the coast and towards the outlet, where the material tends to accumulate, resulting in lake level rise. During cold periods the perennial lake ice cover hampers any wave activity and pebble-transport, keeping the outlet open and causing the lake level to drop. 相似文献
129.
Nicholas L. Balascio Zhaohui Zhang Raymond S. Bradley Svein Olaf Dahl Jostein Bakke 《Quaternary Research》2011,75(1):288-300
This study takes a comprehensive approach to characterizing the isolation sequence of Heimerdalsvatnet, a coastal lake in the Lofoten Islands, northern Norway. We use established methods and explore new techniques to assess changes in marine influence. Bathymetric and sub-bottom profiles were acquired to examine basin-wide sedimentation and a 5.8 m sediment core spanning the last 7800 cal yr BP was analyzed. We measured magnetic susceptibility, bulk organic matter properties, molecular biomarkers, diatom assemblages, and elemental profiles acquired by scanning X-ray fluorescence. These characteristics of the sediment reflect detailed changes in salinity and water column conditions as the lake was progressively isolated. Three distinct litho/chemo-stratigraphic units represent a restricted marine phase (7800-6500 cal yr BP), a transitional phase characterized by intermittent marine influence (6500-4900 cal yr BP), and complete isolation and freshwater sedimentation (4900 cal yr BP to present). Although there are uncertainties in the estimate of the threshold elevation of the lake, the timing of these phases generally corresponds with previous interpretations of the local relative sea-level history. This record captures sea-level regression following the Tapes transgression and supports the interpretation of a subsequent sea-level stillstand, dated in Heimerdalsvatnet from 6500 to 4900 cal yr BP. 相似文献
130.
Joris Gieskes Anthony E. Rathburn Jonathan B. Martin M. Elena Prez Chris Mahn Joan M. Bernhard Shelley Day 《Applied Geochemistry》2011,26(5):738-746
An extensive geochemical and biogeochemical examination of CH4 seeps in the Clam Flats area of Monterey Bay provides insight into the character of relationships between seep geochemistry and benthic foraminiferal geochemistry. The area is characterized by sulfide-rich fluids. Sulfide increases are associated with large increases in alkalinity, as well as small decreases in dissolved Ca and Mg. In addition, only small increases in NH4 are observed, but values of δ13C of dissolved inorganic C are as low as −60‰ at shallow depths (<3 cm). These observations indicate that all these processes are related to the bacterial oxidation of CH4, which is transported upward by slow seepage of pore fluids. The geochemistry of the pore fluids should be relevant to the geochemistry of the carbonate tests of living and dead foraminifera. However, a profound disequilibrium of approximately an order of magnitude occurs between the δ13C values of stained (cytoplasm-containing) foraminiferal carbonate and the C isotope values of ambient pore water dissolved inorganic C. Reasons are unclear for this isotopic disequilibrium, but have important implications for interpretations of foraminiferal carbonate as a paleoenvironmental proxy. Much fine scale work is needed to fully understand the relationships between the biogeochemistry of benthic foraminifera and the geochemistry of the pore waters where they live. 相似文献