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

Establishment of a harmonized tool for calculating river discharge and nitrogen loads from unmonitored areas in Denmark 建立一个统一的工具，用于计算丹麦未监测地区的河流流量和氮负荷

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 Epub Date: 2001-07-13 DOI: 10.1016/S1464-1909(01)00058-2

D.-I. Müller-Wohlfeil , B. Kronvang , S.E. Larsen , N.B. Ovesen , F. Wendland

{"title":"Establishment of a harmonized tool for calculating river discharge and nitrogen loads from unmonitored areas in Denmark","authors":"D.-I. Müller-Wohlfeil , B. Kronvang , S.E. Larsen , N.B. Ovesen , F. Wendland","doi":"10.1016/S1464-1909(01)00058-2","DOIUrl":"10.1016/S1464-1909(01)00058-2","url":null,"abstract":"<div><p>The main objective of the present study is to detect and assess empirical relationships between river discharge and catchment characteristics to support the simulation of nitrogen losses on the regional and national scale. The empirical model derived provides the basis for a comprehensive and harmonized tool for the calculation of annual river discharge and nutrient loads from 49 Danish catchments to coastal waters. The model was applied for the years 1994 and 1995. Results from this application indicate that the simulated values are generally lower than the corresponding values from previous estimations. The main explanation is that precipitation as the most important model parameter shows a distinct gradient towards the coastal areas. This gradient has not been considered by the previously applied regional methods. Although the model results are generally reasonable, improvements are necessary, particularly with respect to the representation of subsurface properties.</p></div>","PeriodicalId":101025,"journal":{"name":"Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere","volume":"26 7","pages":"Pages 617-622"},"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)00058-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84068363","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

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 Epub Date: 2001-03-22 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

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 Epub Date: 2001-07-13 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

Development of an integrated water resources management system in southern african catchments 在南部非洲集水区发展综合水资源管理系统

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 Epub Date: 2001-07-13 DOI: 10.1016/S1464-1909(01)00050-8

H. Staudenrausch, W.A. Flügel

{"title":"Development of an integrated water resources management system in southern african catchments","authors":"H. Staudenrausch, W.A. Flügel","doi":"10.1016/S1464-1909(01)00050-8","DOIUrl":"10.1016/S1464-1909(01)00050-8","url":null,"abstract":"<div><p>Water resources management is a contentious challenge in Southern Africa. Scarce resources, often poor quality, unfavourable temporal and spatial distribution and competing stakeholders characterise the water resources in this region. The following general objectives and techniques are investigated: (a) Development of dynamic water balance and erosion models for three study catchments using remotely sensed and other data, (b) assessment of water demand and usage of the different user sectors and stakeholders, (c) design and simulation of “What if?” scenarios to investigate trends and interactions of the complex water resources planning process, and (d) development and implementation of strategies to solve water allocation conflicts. The product of the project, the prototype IWRMS, is an innovative computer based toolset designed as an assembly of tested, validated and well documented procedures comprising techniques of database management, remote sensing, GIS, process modelling, decision support and implementation strategies. The modelling results and first prototype installations in Southern Africa show the applicability of this system.</p></div>","PeriodicalId":101025,"journal":{"name":"Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere","volume":"26 7","pages":"Pages 561-564"},"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)00050-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73081210","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: 23

Hydrological modelling of the Saone basin sensitivity to the soil model 索恩河流域水文模拟敏感性土壤模型

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 Epub Date: 2001-06-04 DOI: 10.1016/S1464-1909(01)00036-3

D. Thiéry, N. Amraoui

引用次数: 6

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 Epub Date: 2001-04-24 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

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 Epub Date: 2002-04-16 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

River flow forecasting using artificial neural networks 基于人工神经网络的河流流量预测

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 Epub Date: 2002-04-16 DOI: 10.1016/S1464-1909(01)85005-X

Y.B. Dibike, D.P. Solomatine

{"title":"River flow forecasting using artificial neural networks","authors":"Y.B. Dibike, D.P. Solomatine","doi":"10.1016/S1464-1909(01)85005-X","DOIUrl":"10.1016/S1464-1909(01)85005-X","url":null,"abstract":"<div><p>River flow forecasting is required to provide basic information on a wide range of problems related to the design and operation of river systems. The availability of extended records of rainfall and other climatic data, which could be used to obtain stream flow data, initiated the practice of rainfall-runoff modelling. While conceptual or physically-based models are of importance in the understanding of hydrological processes, there are many practical situations where the main concern is with making accurate predictions at specific locations. In such situation it is preferred to implement a simple “black box” (data-driven, or machine learning) model to identify a direct mapping between the inputs and outputs without detailed consideration of the internal structure of the physical process. Artificial neural networks (ANNs) is probably the most successful machine learning technique with flexible mathematical structure which is capable of identifying complex non-linear relationships between input and output data without attempting to reach understanding as to the nature of the phenomena. In this study the applicability of ANNs for downstream flow forecasting in the Apure river basin (Venezuela) was investigated. Two types of ANN architectures, namely multi-layer perceptron network (MLP) and a radial basis function network (RBF) were implemented. The performances of these networks were compared with a conceptual rainfall-runoff model and they were found to be slightly better for this river flow-forecasting problem.</p></div>","PeriodicalId":101025,"journal":{"name":"Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere","volume":"26 1","pages":"Pages 1-7"},"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)85005-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78995045","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: 195

Modeling water flow and mass transport in a loess catchment 黄土流域水流和物质输运模拟

Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere Pub Date : 2001-01-01 DOI: 10.1016/S1464-1909(01)00041-7

E. Zehe, T. Maurer, J. Ihringer, E. Plate

引用次数: 120

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 Epub Date: 2001-04-24 DOI: 10.1016/S1464-1909(01)00012-0

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

引用次数: 51