Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere最新文献_第2页

Numerical simulations of topography-induced saltwater upconing in the state of Brandenburg, Germany 德国勃兰登堡州地形诱导盐水上升的数值模拟

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 DOI: 10.1016/S1464-1909(01)00018-1

A. Voss, M. Koch

{"title":"Numerical simulations of topography-induced saltwater upconing in the state of Brandenburg, Germany","authors":"A. Voss, M. Koch","doi":"10.1016/S1464-1909(01)00018-1","DOIUrl":"10.1016/S1464-1909(01)00018-1","url":null,"abstract":"<div><p>Saltwater intrusion from saline formation waters in the shallow lowlands of the state of Brandenburg, Germany, is simulated using a 2D density-dependent (dd) flow and transport model. Based on the geological situation and the present-day chemical composition of the groundwaters in that region, migration scenarios with and without inclusion of density effects are modelled. We find that, due to the shallowness of the aquifer system, the surficial topography has a large effect on the flow and migration patterns and, especially, gives rises to upwelling flow underneath the discharge area of the Nuthe river. Comparing models, with and without density effects included, we then investigate possible saltwater upconing due this natural discharge flow pattern. A sensitivity study of the hydrodynamic dispersion and of the anisotropy of the aquifer is at the heart of the investigation. The results of the models show that density effects are diminishing for large values of the dispersivity and high anisotropy ratios. This means that for the management of saltwater intrusion, instead of using a complicated dd flow and transport model, it may be sufficient in most practical situation to use a passive transport model, which would have a much smaller computational time.</p></div>","PeriodicalId":101025,"journal":{"name":"Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere","volume":"26 4","pages":"Pages 353-359"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1909(01)00018-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82148796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Modelling long-term trends in UK sulphur deposition 模拟英国硫沉积的长期趋势

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 DOI: 10.1016/S1464-1909(01)00090-9

D.S. Lee, R.D. Kingdon

{"title":"Modelling long-term trends in UK sulphur deposition","authors":"D.S. Lee, R.D. Kingdon","doi":"10.1016/S1464-1909(01)00090-9","DOIUrl":"10.1016/S1464-1909(01)00090-9","url":null,"abstract":"<div><p>On the UK-scale, sulphur dioxide (SO<sub>2</sub>) dry deposition has declined at a faster rate than SO<sub>2</sub> emissions, but S wet deposition has declined at a slower rate than emissions. Three hypotheses have been put forward to explain this non-linear response to changes in emissions: changes in the effective release height of emissions; oxidation of SO<sub>2</sub> may have been oxidant limited in previous years; the canopy resistance of SO<sub>2</sub> has changed in response to changing ammonia concentrations. Of these three hypotheses, the first has been tested here using a 10-layer Lagrangian acid deposition model. The model reproduced the rate of decline of observed total S deposition but not the magnitude. The mismatch in magnitude between modelled and observed UK S deposition is consistent with the model framework and its limitations. More importantly, the model did not reproduce the changes in the proportions of wet and dry deposition to the UK that have been observed using two different sets of UK emission data. The UK-derived emissions data show a small increase in the proportion of low-level SO<sub>2</sub> sources to the total and a small decrease in proportion of the high-level SO<sub>2</sub> sources over the period 1989–1994. These changes are not apparently consistent with observed changes in SO<sub>2</sub> concentrations nor changes in wet and dry S deposition. Thus, it is unsurprising that the modelling does not simulate the observed changes in fractions of wet and dry deposition. The current constraints of the modelling and the emissions data have the consequence that future scenarios of rates of change of total S deposition may be optimistic for locations that are dominated by wet deposition, remote from sources.</p></div>","PeriodicalId":101025,"journal":{"name":"Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere","volume":"26 10","pages":"Pages 813-817"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1909(01)00090-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86517106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Impact of documented land use changes on the surface albedo and evapotranspiration in a plain watershed 文献记载的土地利用变化对平原流域地表反照率和蒸散的影响

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 DOI: 10.1016/S1464-1909(01)00055-7

J. Mika , Sz. Horváth , L. Makra

{"title":"Impact of documented land use changes on the surface albedo and evapotranspiration in a plain watershed","authors":"J. Mika , Sz. Horváth , L. Makra","doi":"10.1016/S1464-1909(01)00055-7","DOIUrl":"https://doi.org/10.1016/S1464-1909(01)00055-7","url":null,"abstract":"<div><p>Agricultural land use series are investigated in a plain catchment area of the Tisza River, almost identically represented by six administrative counties. Each county, commonly covering 34,000 km<sup>2</sup>, is characterised by high percentage (70–80 %) of managed vegetation. Effects of area coverage variations between the different plants are computed for the period 1951–1993 by applying results of a literature-based syntheses, specified for Hungary. The latter studies estimate surface-albedo values and proportion between real and potential evapotranspiration for the great majority of the plants grown in the region. Potential evapotranspiration and relative soil moisture content are estimated from the monthly meteorological series of temperature, precipitation and atmospheric water vapour pressure. Product of these plant-specific characteristics and the relative area coverage yield in monthly series of surface albedo and real evapotranspiration. Furthermore, these values are related to the energy balance of the surface-atmosphere system by using a radiative-convective model adjusted for the given location. Two questions are investigated:</p><p>i) Are there monotonous trends in the given terms of the energy and water budget?</p><p>ii) Are these changes comparable to the effects caused by other external forcings?</p><p>Our computations give positive answer to both questions.</p></div>","PeriodicalId":101025,"journal":{"name":"Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere","volume":"26 7","pages":"Pages 601-606"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1909(01)00055-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91635113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Influence of the Amazon River runoff on the tropical atlantic 亚马逊河径流对热带大西洋的影响

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 DOI: 10.1016/S1464-1909(00)00230-6

S Masson, P Delecluse

{"title":"Influence of the Amazon River runoff on the tropical atlantic","authors":"S Masson, P Delecluse","doi":"10.1016/S1464-1909(00)00230-6","DOIUrl":"https://doi.org/10.1016/S1464-1909(00)00230-6","url":null,"abstract":"<div><p>The Amazon river has the biggest flow in the world, 0.2 Sv (1 Sv = 10<sup>6</sup> m<sup>3</sup>/s), and is responsible for a large part of the low Sea Surface Salinity (SSS) in the west tropical Atlantic ocean. Very few Ocean General Circulation Model (OGCM) include runoff which brings a specific contribution to the Ocean physics. Comparison of simulations with constant or monthly runoffs shows that the spread of the Amazon fresh waters offshore of the north Brazilian coast is controlled by the ocean circulation and not by the Amazon flow. Therefore, in the model like in the observations, SSS minimum is observed in summer three months after the Amazon flood. In agreement with observations, a thick (more than 40 m) Barrier Layer (BL) is present every summer north of the Amazon mouth. Because of the strong and shallow salinity gradient associated with the Amazon freshwater, an important part of the solar radiation is trapped in the BL and creates an inversion of the vertical gradient of temperature. However with this forced model, BL does not seem to have a clear impact on SST and so on the air-sea interaction. Freshwater flux is also able to bend the sea surface. The geostrophic part of the North Brazilian Current (NBC) retroflection is then lightly weaker in presence of the Amazon runoff.</p></div>","PeriodicalId":101025,"journal":{"name":"Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere","volume":"26 2","pages":"Pages 137-142"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1909(00)00230-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91637942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 77

Chaotic advection of reacting substances: Plankton dynamics on a meandering jet 反应物质的混沌平流:浮游生物在蜿蜒射流上的动力学

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 DOI: 10.1016/S1464-1909(01)00012-0

C. López , Z. Neufeld , E. Hernández-García , P.H. Haynes

引用次数: 51

Topographic expressions of bars in channels with variable width 变宽河道中沙洲的地形表达式

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 DOI: 10.1016/S1464-1909(01)85017-6

R. Repetto , M. Tubino

{"title":"Topographic expressions of bars in channels with variable width","authors":"R. Repetto , M. Tubino","doi":"10.1016/S1464-1909(01)85017-6","DOIUrl":"10.1016/S1464-1909(01)85017-6","url":null,"abstract":"<div><p>A three dimensional quasi-analytical model is introduced to determine the flow field and the altimetric response of movable-bed channels subject to periodic width variations. The basic assumptions underlying the analysis are those of small amplitude of width variations and wide channel, so that non linear effects and side wall effects are neglected. The aim of the work is to determine the conditions under which the channel is planimetrically stable or unstable, i.e. it tends to damp (or enhance) a given initial (infinitesimal) perturbation of the channel width due to bank erosion. A simple bank erosion model is adopted whereby the rate of bank retreat is related to the excess shear stress at the banks. Theoretical results suggest that the equilibrium bottom profile is mainly constituted by two components. The first component represents a purely longitudinal bottom deformation, which induces deposition at the widest section and scour at the constraint, where the cross sectionally averaged velocity attains its maximum value. The second component is mainly originated by three dimensional effects and induces a transverse deformation of the bed in the form of a central bar. Its relative position with respect to the former component changes with the length of width variations: under suitable conditions the flow divergence induced by the central bar leads to a maximum velocity at the banks in wide sections, which implies that width variations tend to amplify.</p></div>","PeriodicalId":101025,"journal":{"name":"Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere","volume":"26 1","pages":"Pages 71-76"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1909(01)85017-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88195859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Modelling sediment transfer in Malawi: comparing backpropagation neural network solutions against a multiple linear regression benchmark using small data sets 马拉维泥沙转移建模:使用小数据集比较反向传播神经网络解决方案与多元线性回归基准

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 DOI: 10.1016/S1464-1909(01)85008-5

R.J. Abrahart , S.M. White

引用次数: 87

The semi-arid integrated model (SIM), a regional integrated model assessing water availability, vulnerability of ecosystems and society in NE-Brazil 半干旱综合模型(SIM):一个评估巴西东北部水资源可得性、生态系统和社会脆弱性的区域综合模型

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 DOI: 10.1016/S1464-1909(01)00045-4

M.S Krol, A Jaeger, A Bronstert, J Krywkow

{"title":"The semi-arid integrated model (SIM), a regional integrated model assessing water availability, vulnerability of ecosystems and society in NE-Brazil","authors":"M.S Krol, A Jaeger, A Bronstert, J Krywkow","doi":"10.1016/S1464-1909(01)00045-4","DOIUrl":"10.1016/S1464-1909(01)00045-4","url":null,"abstract":"<div><p>Northeastern Brazil, an example of vulnerable semi-arid regions on the earth, is characterised by water scarcity and vulnerability of natural resources, pronounced climatic variability and social stress situations. Integrated studies involving hydrology, ecology, meteorology, climatology, pedology, agronomy, and social and economic sciences are required not only for analysing consequences of the adverse natural conditions but also to assess possible strategies to make semi-arid regions less vulnerable to the present and changing climate.</p><p>Integrated modelling of the relationships between water availability, quality of life and migration, including aspects of global change processes, in the <em>Semi-arid Integrated Model</em> (SIM) serves to understand the dynamics of the system. An overview of the concept, structure and application results of the integrated model are given.</p><p>A sensitivity study on climate change illustrates potentially significant adverse effects on the region. Moreover, it shows that a regional integrated model is a suitable tool for complex and interdisciplinary studies. The present version of SIM still is in a development phase, especially in its representation of socio-economic processes.</p></div>","PeriodicalId":101025,"journal":{"name":"Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere","volume":"26 7","pages":"Pages 529-533"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1909(01)00045-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90755495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 56

Lagrangian transport of particles in Ria de Aveiro lagoon, Portugal 葡萄牙Ria de Aveiro泻湖中粒子的拉格朗日输运

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 DOI: 10.1016/S1464-1909(01)00076-4

J.M. Dias , J.F. Lopes , I. Dekeyser

引用次数: 0

A modelling study of seawater intrusion in the Korba coastal plain, Tunisia 突尼斯科尔巴沿海平原海水入侵的模拟研究

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 DOI: 10.1016/S1464-1909(01)00017-X

C. Paniconi , I. Khlaifi , G. Lecca , A. Giacomelli , J. Tarhouni

{"title":"A modelling study of seawater intrusion in the Korba coastal plain, Tunisia","authors":"C. Paniconi , I. Khlaifi , G. Lecca , A. Giacomelli , J. Tarhouni","doi":"10.1016/S1464-1909(01)00017-X","DOIUrl":"10.1016/S1464-1909(01)00017-X","url":null,"abstract":"<div><p>A numerical model that treats density-dependent variably saturated flow and miscible salt transport is used to investigate the occurrence of seawater intrusion in the Korba coastal plain of northeastern Tunisia. We examine the effects of and interplay between pumping, artificial recharge, soil/aquifer properties, and the unsaturated zone. The data processing steps undertaken in this study are briefly described, and a critical assessment is given of the data availability and of the requirements for successful monitoring and modeling of seawater intrusion risks in heavily exploited coastal aquifers such as those found in the semi-arid regions of the Mediterranean basin. An idea of the extent of over-exploitation of the Korba aquifer is obtained by examining the pumping and rainfall/infiltration data, and the simulation results support groundwater pumping as the mechanism for and seawater intrusion as the origin of the salt contamination observed in the soils and subsurface waters of the Korba plain.</p></div>","PeriodicalId":101025,"journal":{"name":"Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere","volume":"26 4","pages":"Pages 345-351"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1909(01)00017-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73462478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 71