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Benjamin de Brye Anouk de Brauwere Olivier Gourgue Tuomas Kärnä Jonathan Lambrechts Richard Comblen Eric Deleersnijder 《Coastal Engineering》2010
We report on the development and validation of a coupled two- and one-dimensional finite-element model for the Scheldt tributaries, river, estuary and region of fresh water influence (ROFI). The hydrodynamic equations are solved on a single, unstructured, multi-scale mesh stretching from the shelf break to the Scheldt tributaries. The tide is forced on the shelf break and propagates upstream in the riverine network. Upstream boundaries lie on sluices or outside of the region of tidal dominance where daily averaged discharges are imposed. Two-dimensional, depth-averaged shallow water equations are solved by means of the discontinuous Galerkin (DG) method over the marine and estuarine parts of the computational domain. In the rivers, however, one-dimensional equations are dealt with using the DG method with the addition of a technique to cope with confluence points. Model parameters are carefully calibrated, leading to the simulation of wind- and tide-forced flows that are in excellent agreement with available data. The diffusivity in the transport equation is calibrated using time series of salinity at various locations in the estuary. Finally, the Lagrangian residual transport in the estuary and the adjacent coastal zone is investigated. This work is a major step towards an integrated model for studying the dynamics of waterborne contaminants and the water renewal timescales in the Scheldt land-sea continuum. 相似文献
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Joni Virkkunen 《GeoJournal》1999,48(2):83-89
Identity has become one of the core concepts of political geography. This reflects the wide recognition of a post-structural conception of society and space, as well as the acknowledgement of the political character of identity. The present article focuses on the politics of identity, and discusses the politicized forms of identity as related to the Soviet state building policies and the Estonian spaces of resistance. It will be argued that neither identity nor the political demand in Soviet Estonia can be viewed in isolation from their historical and social contexts. Both Soviet state politics and the Estonian spaces of resistance reflected the prevailing conceptions of past and the contemporary political realities. This article examines those preconceptions of the political and territorial development in Soviet Estonia, and also illustrates the interdependent character of state politics and non-state activism. The first part of the article concentrates on the Soviet state building practices – the use of power, symbols, education – and the second part examines the various forms of non-state activism of Estonians. 相似文献
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Ocean Dynamics - Currents in the Baltic Sea are generally weak, but during strong winds they can grow high enough to affect the surface wave propagation and evolution. To evaluate the significance... 相似文献
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Øystein Elgarøy Tuomas Multamäki 《Monthly notices of the Royal Astronomical Society》2005,356(2):475-479
An alternative to dark energy as an explanation for the present phase of accelerated expansion of the Universe is that the Friedmann equation is modified, e.g. by extra dimensional gravity, on large scales. We explore a natural parametrization of a general modified Friedmann equation, and find that the present supernova Type Ia and cosmic microwave background data prefer a correction of the form 1/ H to the Friedmann equation over a cosmological constant. 相似文献
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This article examines age variations in support for environmental protection policies that affect climate change using a sample of over 14,000 respondents to a 1999 Eurobarometer survey. There is a steady decline with age in whether respondents are willing to incur higher gasoline prices to protect the environment. This relationship remains after controlling for socioeconomic characteristics. There are age-related differences in information about environmental risks, information sources about the environment, perceived health risks from climate change, and degree of worry about climate change. However, taking these factors into account does not eliminate the age variation in willingness to pay more for gasoline to protect the environment. 相似文献
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Shorefaces play a critical role in cross‐shore sediment transport between the beach and inner shelf, particularly during storm conditions. A comparison and examination of storm‐driven sedimentary changes on two adjacent shorefaces in Northern Ireland, located only 5 km apart, revealed significantly different geomorphological responses. The steeper shoreface at West Strand responded with extensive sediment deposition across almost the entire shoreface, in contrast with the more dissipative and quasi‐linear shoreface at Portstewart, which mostly showed nearshore bar changes. Results from the two sites, which have similar wave/wind characteristics and seabed sediments, suggest that: (i) cross‐shore morphology, (ii) immediately previous (antecedent) shoreface morphodynamic behaviour and (iii) the presence, or lack of, offshore sand appear to be the primary controls on storm‐driven sedimentary changes attributed to the high‐energy event. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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The performance of a linear resuspension model developed in the Baltic Sea was studied in the conditions of a eutrophic Lake Kirkkoj(a|¨)rvi(southern Finland).The model predicts sediment resuspension rate using data on vegetation cover,wind and sediment quality as an input.When the original model coefficients were used,the model resulted on average 1.8 fold overestimation of the resuspension rate in Kirkkoj(a|¨)rvi.This was due to lower fetch and water depth,and less consolidated sediment of Kirkkoj(a|¨)rvi compared with the Baltic Sea study site.When coefficients were adjusted for Kirkkoj(a|¨)rvi,the model predictions were 1.1 times the measured values.Due to the continuous resuspension,the effect of the wind term in the model was so low that it could be excluded without affecting the accuracy of model predictions.The study demonstrated that in a shallow eutrophic lake accurate predictions on resuspension rate can be made using only data on sediment quality and on factors inhibiting resuspension(macrophytes).The model residuals increased with increasing resuspension rate and high rates of resuspension were underestimated by the model.Due to the fluffy sediment in Kirkkoj(a|¨)rvi,erosion of sediment increases more than linear with increasing shear stress.Thus in such conditions,even better predictions could be achieved by a non-linear resuspension model. 相似文献
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Endra Gunawan Putra Maulida Irwan Meilano Masyhur Irsyam Joni Efendi 《Acta Geophysica》2016,64(6):2136-2150
Based on continuous GPS data, we analyze coseismic deformation due to the 2012 Indian Ocean earthquake. We use the available coseismic slip models of the 2012 earthquake, derived from geodetic and/or seismic waveform inversion, to calculate the coseismic displacements in the Andaman-Nicobar, Sumatra and Java. In our analysis, we employ a spherical, layered model of the Earth and we find that Java Island experienced coseismic displacements up to 8 mm, as also observed by our GPS network. Compared to coseismic offsets measured from GPS data, a coseismic slip model derived from multiple observations produced better results than a model based on a single type of observation. 相似文献
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