HYDRODYNAMIC MODELLING OF ESTUARINE CIRCULATION USING A SPLINE METHOD OF FRACTIONAL STEPS     

Pu Wang  R. Kahawita Professor of Mechanics  Lenzhou University  Lanzhou  China. Professor of Civil Ensineering  Ecole Polytechnique de Montreal Canada. 《国际泥沙研究》1990,(1)

I. INTRODUCTIONNumerical models of estuaries incorporating simulation of the density induced circulation are consideredimPOrtant tools in the assessment of their dispersive characteristics. Most models to date have used finite difference approximations to the governing equations (see for example thericke and Hogan, 1977, Blumberg,1 977, Perrels and Karelse, 1978). A numeriCal model of estuarine circulation using a SADI (Spline Alternating Direction implicit) procedure together with a…  相似文献   

Preparation and application of engineering and environmental geological maps in The Netherlands     

E.F.J. de Mulder  R. Hillen 《Engineering Geology》1990,29(4):279-290

The Netherlands has no nation-wide mapping programme for either engineering geology or environmental geology, but on request the Geological Survey of The Netherlands, together with other geoscientific institutes, prepares: (1) detailed (1:5,000) engineering geological maps of urban areas, specifically meant for urban planning and management as well as for feasibility studies for civil engineering works; and (2) small-scale (1:250,000 to 1:50,000) thematic environmental geological maps, meant for regional landuse planning. The preparation and application of these maps is discussed, and some examples are given.  相似文献   

Model-free estimation from spatial samples: A reappraisal of classical sampling theory   总被引：1，自引：0，他引：1  

J. J. de Gruijter  C. J. F. ter Braak 《Mathematical Geology》1990,22(4):407-415

A commonly held view among geostatisticians is that classical sampling theory is inapplicable to spatial sampling because spatial data are dependent, whereas classical sampling theory requires them to be independent. By comparing the assumptions and use of classical sampling theory with those of geostatistical theory, we conclude that this view is both false and unfortunate. In particular, estimates of spatial means based on classical sampling designs require fewer assumptions for their validity, and are therefore more robust, than those based on a geostatistical model.  相似文献   

Characterization of Estonian Kukersite by spectroscopy and pyrolysis: Evidence for abundant alkyl phenolic moieties in an Ordovician, marine, type II/I kerogen     

S. Derenne  C. Largeau  E. Casadevall  J.S. Sinninghe Damst  E.W. Tegelaar  J.W. de Leeuw 《Organic Geochemistry》1990,16(4-6)

The kerogen of a sample of Estonian Kukersite (Ordovician) was examined by spectroscopic (solid state ¹³C NMR, FTIR) and pyrolytic (“off-line”, flash) methods. This revealed an important contribution of long, linear alkyl chains in Kukersite kerogen. The hydrocarbons formed upon pyrolysis are dominated by n-alkanes and n-alk-1-enes and probably reflect a major contribution of selectivity preserved, highly aliphatic, resistant biomacromolecules from the outer cell walls of Gloeocapsomorpha prisca. This is consistent with the abundant presence of this fossilized organism in Kukersite kerogen. In addition high amounts of phenolic compounds were identified in the pyrolysates. Series of non-methylated, mono-, di- and trimethylated 3-n-alkylphenols, 5-n-alkyl-1,3-benzenediols and n-alkylhydroxybenzofurans were identified. All series of phenolic compounds contain long (up to C₁₉), linear alkyl side-chains. Kukersite kerogen is, therefore, an aliphatic type II/I kerogen, despite the abundance of free phenolic moieties. This study shows that phenol-derived moieties are not necessarily associated with higher plant-derived organic matter.The flash pyrolysate of Kukersite kerogen was also compared with that of the kerogen of the Guttenberg Oil Rock (Ordovician) which is also composed of accumulations of fossilized G. prisca. Similarities in the distributions of hydrocarbons and sulphur compounds were noted, especially for the C₁–C₆ alkylbenzene and alkylthiophene distributions. However, no phenolic compounds were detected in the flash pyrolysate of the Guttenberg kerogen. Possible explanations for the observed similarities and differences are discussed.  相似文献   

Travel　time　tomography　inversion　and　the　deep　structure　of　the　southern　Tibet   总被引：2，自引：0，他引：2  

吕庆田  姜枚  ＫＡＩ－ＹＩＭＡ  Ａ．Ｈｉｒｎ  Ａ．Ｎｅｒｃｅｓｉａｎ 《地震学报(英文版)》1996,9(4):583-592

ＴｒａｖｅｌｔｉｍｅｔｏｍｏｇｒａｐｈｙｉｎｖｅｒｓｉｏｎａｎｄｔｈｅｄｅｅｐｓｔｒｕｃｔｕｒｅｏｆｔｈｅｓｏｕｔｈｅｒｎＴｉｂｅｔＱＩＮＧ－ＴＩＡＮＬＵ１）（吕庆田）,ＭＥＩ－ＪＩＡＮＧ１）（姜枚）,ＫＡＩ－ＹＩＭＡ１）（马开义）,Ａ．Ｈｉｒｎ２...  相似文献   

Complex coastal change in response to autogenic basin infilling: An example from a sub‐tropical Holocene strandplain          下载免费PDF全文

Christopher J. Hein  Duncan M. FitzGerald  Luis H. P. de Souza  Ioannis Y. Georgiou  Ilya V. Buynevich  Antonio H. da F. Klein  João Thadeu de Menezes  William J. Cleary  Thelma L. Scolaro 《Sedimentology》2016,63(6):1362-1395

Thick bay‐fill sequences that often culminate in strandplain development serve as important sedimentary archives of land–ocean interaction, although distinguishing between internal and external forcings is an ongoing challenge. This study employs sediment cores, ground‐penetrating radar surveys, radiocarbon dates, palaeogeographic reconstructions and hydrodynamic modelling to explore the role of autogenic processes – notably a reduction in wave energy in response to coastal embayment infilling – in coastal evolution and shoreline morphodynamics. Following a regional 2 to 4 m highstand at ca 5·8 ka, the 75 km² Tijucas Strandplain in southern Brazil built from fluvial sediments deposited into a semi‐enclosed bay. Holocene regressive deposits are underlain by fluvial sands and a Pleistocene transgressive–regressive sequence, and backed by a highstand barrier‐island. The strandplain is immediately underlain by 5 to 16 m of seaward‐thickening, fluvially derived, Holocene‐age, basin‐fill mud. Several trends are observed from the landward (oldest) to the seaward (youngest) sections of the strandplain: (i) the upper shoreface and foreshore become finer and thinner and shift from sand‐dominated to mud‐dominated; (ii) beachface slopes decrease from >11° to ca 7°; and (iii) progradation rates increase from 0·4 to 1·8 m yr^?1. Hydrodynamic modelling demonstrates a correlation between progressive shoaling of Tijucas Bay driven by sea‐level fall and sediment infilling and a decrease in onshore wave‐energy transport from 18 to 4 kW m^?1. The combination of allogenic (sediment supply, falling relative sea‐level and geology) and autogenic (decrease in wave energy due to bay shoaling) processes drove the development of a regressive system with characteristics that are rare, if not unique, in the Holocene and rock records. These findings demonstrate the complexities in architecture styles of highstand and regressive systems tracts. Furthermore, this article highlights the diverse internal and external processes and feedbacks responsible for the development of these intricate marginal marine sedimentary systems.  相似文献   

Fluid-mediated alteration of (Y,REE,U,Th)–(Nb,Ta,Ti) oxide minerals in granitic pegmatite from the Evje-Iveland district,southern Norway     

Charley J. Duran  Anne-Magali Seydoux-Guillaume  Bernard Bingen  Sophie Gouy  Philippe de Parseval  Jannick Ingrin  Damien Guillaume 《Mineralogy and Petrology》2016,110(5):581-599

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Flood-related leptospirosis outbreaks in Brazil: perspectives for a joint monitoring by health services and disaster monitoring centers     

Luciana de Resende Londe  Rodrigo Silva da Conceição  Tiago Bernardes  Mariane Carvalho de Assis Dias 《Natural Hazards》2016,84(2):1419-1435

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Riverine dominance of a nearshore marine demersal food web: evidence from stable isotope and C/N ratio analysis     

AM de Lecea  AJ Smit  ST Fennessy 《African Journal of Marine Science》2016,38(1):S181-S192

The Thukela Bank, KwaZulu-Natal, supports a diverse ecosystem and South Africa’s only prawn fishery. Oceanographic studies suggest riverine input is not important for the biology of this system, whereas biological studies suggest the contrary, with prawn catches increasing with increased fluvial run-off. The aim of this study was to determine (i) the importance of riverine and marine organic matter for the Thukela Bank food web; and (ii) whether there are seasonal changes in the Thukela River stable isotope values, and, if so, whether these are reflected in the isotope values of demersal organisms. Estuarine organic matter, sediments and demersal organisms were collected from several sites across the bank in the wet and dry seasons of 2008, 2009 and 2010. Marine particulate organic matter was also collected in 2010 and analysed for δ13C and δ15N, as well as C/N ratios. There were strong seasonal changes in isotopic values of organic matter and fauna, especially faunal δ13C. There was an apparent time-lag in organisms assimilating riverine organic matter isotopic values, with the isotopic signature of demersal organisms reflecting that of riverine organic matter from the previous season, which is likely the result of tissue turnover time. In 2010, Thukela Bank sediment organic matter was of riverine origin and this maintained the demersal food web. We conclude that Thukela River organic matter is an important input to the food web of the Thukela Bank, indicating that any future damming of the catchment area could have serious consequences for this ecosystem.  相似文献   

Global fossil energy markets and climate change mitigation – an analysis with REMIND     

Nico?BauerEmail author  Ioanna?Mouratiadou  Gunnar?Luderer  Lavinia?Baumstark  Robert?J.?Brecha  Ottmar?Edenhofer  Elmar?Kriegler 《Climatic change》2016,135(1):69-83

We analyze the dynamics of global fossil resource markets under different assumptions for the supply of fossil fuel resources, development pathways for energy demand, and climate policy settings. Resource markets, in particular the oil market, are characterized by a large discrepancy between costs of resource extraction and commodity prices on international markets. We explain this observation in terms of (a) the intertemporal scarcity rent, (b) regional price differentials arising from trade and transport costs, (c) heterogeneity and inertia in the extraction sector. These effects are captured by the REMIND model. We use the model to explore economic effects of changes in coal, oil and gas markets induced by climate-change mitigation policies. A large share of fossil fuel reserves and resources will be used in the absence of climate policy leading to atmospheric GHG concentrations well beyond a level of 550 ppm CO₂-eq. This result holds independently of different assumptions about energy demand and fossil fuel availability. Achieving ambitious climate targets will drastically reduce fossil fuel consumption, in particular the consumption of coal. Conventional oil and gas as well as non-conventional oil reserves are still exhausted. We find the net present value of fossil fuel rent until 2100 at 30tril.US$ with a large share of oil and a small share of coal. This is reduced by 9 and 12tril.US$ to achieve climate stabilization at 550 and 450 ppm CO₂-eq, respectively. This loss is, however, overcompensated by revenues from carbon pricing that are 21 and 32tril.US$, respectively. The overcompensation also holds under variations of energy demand and fossil fuel supply.  相似文献