Articles de revues : « Hydrology Mathematical models »

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Mulla, D. J. « Mathematical Models of Small Watershed Hydrology and Applications ». Journal of Environmental Quality 32, n^o 1 (janvier 2003) : 374. http://dx.doi.org/10.2134/jeq2003.374a.

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Sawada, Yohei, et Risa Hanazaki. « Socio-hydrological data assimilation : analyzing human–flood interactions by model–data integration ». Hydrology and Earth System Sciences 24, n^o 10 (5 octobre 2020) : 4777–91. http://dx.doi.org/10.5194/hess-24-4777-2020.

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Abstract. In socio-hydrology, human–water interactions are simulated by mathematical models. Although the integration of these socio-hydrological models and observation data is necessary for improving the understanding of human–water interactions, the methodological development of the model–data integration in socio-hydrology is in its infancy. Here we propose applying sequential data assimilation, which has been widely used in geoscience, to a socio-hydrological model. We developed particle filtering for a widely adopted flood risk model and performed an idealized observation system simulation experiment and a real data experiment to demonstrate the potential of the sequential data assimilation in socio-hydrology. In these experiments, the flood risk model's parameters, the input forcing data, and empirical social data were assumed to be somewhat imperfect. We tested if data assimilation can contribute to accurately reconstructing the historical human–flood interactions by integrating these imperfect models and imperfect and sparsely distributed data. Our results highlight that it is important to sequentially constrain both state variables and parameters when the input forcing is uncertain. Our proposed method can accurately estimate the model's unknown parameters – even if the true model parameter temporally varies. The small amount of empirical data can significantly improve the simulation skill of the flood risk model. Therefore, sequential data assimilation is useful for reconstructing historical socio-hydrological processes by the synergistic effect of models and data.

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Milks, Robert R., William C. Fonteno et Roy A. Larson. « Hydrology of Horticultural Substrates : I. Mathematical Models for Moisture Characteristics of Horticultural Container Media ». Journal of the American Society for Horticultural Science 114, n^o 1 (janvier 1989) : 48–52. http://dx.doi.org/10.21273/jashs.114.1.48.

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Abstract Moisture retention data were collected for five porous materials: soil, phenolic foam, and three combinations of commonly used media components. Two mathematical functions were evaluated for their ability to describe the water content–soil moisture relationship. A cubic polynomial function with linear parameters previously used on container media was compared to a closed-form nonlinear parameter model developed to describe water conductivity in mineral soils. In most tests for precision, adequacy, accuracy, and validation, the nonlinear function was superior to the simpler power series. The nonlinear function provides an excellent tool for describing the water content for media with widely varying physical properties.

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Mańko, Robert, et Norbert Laskowski. « Comparative analysis of the effectiveness of the conceptual rainfall-runoff hydrological models on the selected rivers in Odra and Vistula basins ». ITM Web of Conferences 23 (2018) : 00025. http://dx.doi.org/10.1051/itmconf/20182300025.

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Identification of physical processes occurred in the watershed is one of the main tasks in hydrology. Currently the most efficient hydrological processes describing and forecasting tool are mathematical models. They can be defined as a mathematical description of relations between specified attributes of analysed object. It can be presented by: graphs, arrays, equations describing functioning of the object etc. With reference to watershed a mathematical model is commonly defined as a mathematical and logical relations, which evaluate quantitative dependencies between runoff characteristics and factors, which create it. Many rainfall-runoff linear reservoirs conceptual models have been developed over the years. The comparison of effectiveness of Single Linear Reservoir model, Nash model, Diskin model and Wackermann model is presented in this article.

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Sun, Si Miao, Chang Lei Dai, Hou Chu Liao et Di Fang Xiao. « A Conceptual Model of Soil Moisture Movement in Seasonal Frozen Unsaturated Zone ». Applied Mechanics and Materials 90-93 (septembre 2011) : 2612–18. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.2612.

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Conceptual model is considered as one of the crucial and essential methods for scientific research on cold region hydrology. However, graphical conceptual model that integrates with a variety of influencing factors and specializes in describing soil moisture dynamic in seasonal frozen unsaturated zone has never occurred in any related researches, due to which the study on mechanism of frozen soil moisture movement has been delayed in a certain degree. Firstly, three stages of freezing and thawing process are divided in this article to serve for the further study in seasonal frozen unsaturated zone, which respectively are: the Stage of Freezing (Instable Freezing Stage and Stable Freezing Stage), the Stage of Thawing (Instable Thawing Stage and Stable Thawing Stage) and the Stage of Freeze-free. Secondly, based on different stages above, three characteristics and the relationships are analyzed, which include freeze-thaw-action and groundwater table, freeze-thaw-action and groundwater storage, freeze-thaw-action and soil surface evaporation. Thirdly, referred to related theories (Frozen Soil Hydrology and Snow & Ice Hydrology) and the construction of watershed model in warm regions, a whole set of graphical conceptual model and corresponding symbolic model have been built with freezing and thawing process as x-axis (time coordinate) and both soil frozen depth and different parameters as double y-axis. The different parameters include groundwater depth, soil water moisture rate and soil surface evaporation intensity. The graphical and symbolic conceptual models comprehensively describe the entire process and the factors relationships of soil moisture movement in seasonal frozen unsaturated zone. These models are expected to provide scientific basis for practical work in cold areas, such as hydrologic and hydraulic calculation in cold seasons, assessment and utilization of frozen area water resources and agricultural irrigation in cold regions, and also to provide references to the development of mathematical or experimental models in related researching fields.

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Ponnambalam, Kumaraswamy, et S. Jamshid Mousavi. « CHNS Modeling for Study and Management of Human–Water Interactions at Multiple Scales ». Water 12, n^o 6 (14 juin 2020) : 1699. http://dx.doi.org/10.3390/w12061699.

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This paper presents basic definitions and challenges/opportunities from different perspectives to study and control water cycle impacts on society and vice versa. The wider and increased interactions and their consequences such as global warming and climate change, and the role of complex institutional- and governance-related socioeconomic-environmental issues bring forth new challenges. Hydrology and integrated water resources management (IWRM from the viewpoint of an engineering planner) do not exclude in their scopes the study of the impact of changes in global hydrology from societal actions and their feedback effects on the local/global hydrology. However, it is useful to have unique emphasis through specialized fields such as hydrosociology (including the society in planning water projects, from the viewpoint of the humanities) and sociohydrology (recognizing the large-scale impacts society has on hydrology, from the viewpoint of science). Global hydrological models have been developed for large-scale hydrology with few parameters to calibrate at local scale, and integrated assessment models have been developed for multiple sectors including water. It is important not to do these studies with a silo mindset, as problems in water and society require highly interdisciplinary skills, but flexibility and acceptance of diverse views will progress these studies and their usefulness to society. To deal with complexities in water and society, systems modeling is likely the only practical approach and is the viewpoint of researchers using coupled human–natural systems (CHNS) models. The focus and the novelty in this paper is to clarify some of these challenges faced in CHNS modeling, such as spatiotemporal scale variations, scaling issues, institutional issues, and suggestions for appropriate mathematical tools for dealing with these issues.

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Vieux, Baxter E. « Review of Mathematical Models of Large Watershed Hydrology by Vijay P. Singh and Donald K. Prevert ». Journal of Hydraulic Engineering 130, n^o 1 (janvier 2004) : 89–90. http://dx.doi.org/10.1061/(asce)0733-9429(2004)130:1(89).

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Paz Pellat, Fernando, Jaime Garatuza Payán, Víctor Salas Aguilar, Alma Socorro Velázquez Rodríguez et Martín Alejandro Bolaños González. « Budyko-Type Models and the Proportionality Hypothesis in Long-Term Water and Energy Balances ». Water 14, n^o 20 (20 octobre 2022) : 3315. http://dx.doi.org/10.3390/w14203315.

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In the perspective of Darwinian hydrology, Budyko hypotheses can be the foundation of approaches for developing models. Numerous Budyko-type models meeting established boundary conditions (water and energy limits) have been developed based on the Budyko hypothesis on the long-term-average annual mass and energy balance. Some of these models are grounded on empirical bases, while others have been formulated on sophisticated mathematical developments. We analyze the basic hypotheses underlying some Budyko-type models; we first describe some published models and then examine their underlying hypotheses in a hydrologically intuitive space (precipitation versus runoff). The analyses show that the models studied are a consequence of assuming that two parallel straight lines (of unit slope) of different intercepts are indeed equal (proportionality hypothesis). This hypothesis gives rise to different Budyko-type models that, although mathematically correct and meeting the limits (partially) related to the Budyko hypotheses, do not yield any information about what happens between those limits. To overcome the extreme energy limit, an expolinear model is introduced.

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Rezaie-Balf, Mohammad, et Ozgur Kisi. « New formulation for forecasting streamflow : evolutionary polynomial regression vs. extreme learning machine ». Hydrology Research 49, n^o 3 (27 mars 2017) : 939–53. http://dx.doi.org/10.2166/nh.2017.283.

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Abstract Streamflow forecasting is crucial in hydrology and hydraulic engineering since it is capable of optimizing water resource systems or planning future expansion. This study investigated the performances of three different soft computing methods, multilayer perceptron neural network (MLPNN), optimally pruned extreme learning machine (OP-ELM), and evolutionary polynomial regression (EPR) in forecasting daily streamflow. Data from three different stations, Soleyman Tange, Perorich Abad, and Ali Abad located on the Tajan River of Iran were used to estimate the daily streamflow. MLPNN model was employed to determine the optimal input combinations of each station implementing evaluation criteria. In both training and testing stages in the three stations, the results of comparison indicated that the EPR technique would generally perform more efficiently than MLPNN and OP-ELM models. EPR model represented the best performance to simulate the peak flow compared to MLPNN and OP-ELM models while the MLPNN provided significantly under/overestimations. EPR models which include explicit mathematical formulations are recommended for daily streamflow forecasting which is necessary in watershed hydrology management.

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Kinar, Nicholas J. « Introducing electronic circuits and hydrological models to postsecondary physical geography and environmental science students : systems science, circuit theory, construction, and calibration ». Geoscience Communication 4, n^o 2 (13 avril 2021) : 209–31. http://dx.doi.org/10.5194/gc-4-209-2021.

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Abstract. A classroom activity involving the construction, calibration, and testing of electronic circuits was introduced to an advanced hydrology class at the postsecondary level. Two circuits were constructed by students: (1) a water detection circuit and (2) a hybrid relative humidity (RH)/air temperature sensor and pyranometer. The circuits motivated concepts of systems science, modelling in hydrology, and model calibration. Students used the circuits to collect data useful for providing inputs to mathematical models of hydrological processes. Each student was given the opportunity to create a custom hydrological model within the context of the class. This is an example of constructivist teaching where students engage in the creation of meaningful knowledge, and the instructor serves as a facilitator to assist students in the achievement of a goal. Analysis of student-provided feedback showed that the circuit activity motivated, engaged, and facilitated learning. Students also found the activity to be a novel and enjoyable experience. The theory of circuit operation and calibration is provided along with a complete bill of materials (BOM) and design files for replication of this activity in other postsecondary classrooms. Student suggestions for improvement of the circuit activity are presented along with additional applications.

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Morbidelli, Renato, Corrado Corradini, Carla Saltalippi, Alessia Flammini, Jacopo Dari et Rao Govindaraju. « Rainfall Infiltration Modeling : A Review ». Water 10, n^o 12 (18 décembre 2018) : 1873. http://dx.doi.org/10.3390/w10121873.

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Infiltration of water into soil is a key process in various fields, including hydrology, hydraulic works, agriculture, and transport of pollutants. Depending upon rainfall and soil characteristics as well as from initial and very complex boundary conditions, an exhaustive understanding of infiltration and its mathematical representation can be challenging. During the last decades, significant research effort has been expended to enhance the seminal contributions of Green, Ampt, Horton, Philip, Brutsaert, Parlange and many other scientists. This review paper retraces some important milestones that led to the definition of basic mathematical models, both at the local and field scales. Some open problems, especially those involving the vertical and horizontal inhomogeneity of the soils, are explored. Finally, rainfall infiltration modeling over surfaces with significant slopes is also discussed.

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Garbrecht, Jurgen D. « Review of Mathematical Models of Small Watershed Hydrology and Applications by Vijay P. Singh and Donald K. Frevert ». Journal of Hydraulic Engineering 129, n^o 7 (juillet 2003) : 558–59. http://dx.doi.org/10.1061/(asce)0733-9429(2003)129:7(558).

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Jocea, Andreea Florina, E. G. Crăciun et A. Anton. « Approximation Of Scours Using Terrestrial 3D Laser Scanning ». Journal of Applied Engineering Sciences 5, n^o 1 (1 mai 2015) : 31–36. http://dx.doi.org/10.1515/jaes-2015-0004.

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Abstract In designing artwork as bridges, hydraulic calculations have a very important role due to the fact that they are behind their sizing. Bridge designer must therefore possess knowledge of hydrology, hydraulics of bridges and river banks regularization. A problem that arises during the design stage of bridges is the scour phenomenon surrounding bridge pier. Over time, there have been conducted a number of studies which led to the provision of a plurality of mathematical models that are intended scour prediction. In the present article we will present an experimental study to determine the bed profile and measurement of scours products around a pier bridge using 3D terrestrial laser scanner.

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Chipepa, Fastel, Thatayaone Moakofi et Broderick Oluyede. « Marshall-Olkin-Odd Power Generalized Weibull-G Family of Distributions with Applications of COVID-19 Data ». Journal of Probability and Statistical Science 20, n^o 1 (3 octobre 2022) : 1–20. http://dx.doi.org/10.37119/jpss2022.v20i1.509.

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Attempts have been made to define new families of distributions that provide more flexibility for modelling data that is skewed in nature. In this work, we propose a new family of distributions called Marshall-Olkin-odd power generalized Weibull (MO-OPGW-G) distribution based on the generator pioneered by Marshall and Olkin [20]. This new family of distributions allows for a flexible fit to real data from several fields, such as engineering, hydrology and survival analysis. The mathematical and statistical properties of these distributions are studied and its model parameters are obtained through the maximum likelihood method. We finally demonstrate the effectiveness of these models via simulation experiments and applications to COVID-19 daily deaths data sets.

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ALI MUNZER, SULEIMAN, D. S. BEGLYAROV et R. R. SHAKIROV. « FEATURES AND ANALYSIS OF STUDIES OF FISH PROTECTION COMPLEX FOR WATER RECEIVERS OF LARGE HIGH-PRESSURE HYDROELECTRIC POWER PLANTS ». Prirodoobustrojstvo, n^o 2 (2022) : 86–93. http://dx.doi.org/10.26897/1997-6011-2022-2-86-93.

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Development of effective fish protection measures at water intakes is one of the main directions of fish resources conservation and reproduction in inland water bodies of the country. Its complexity is associated with the involvement of many related disciplines: ichthyology, physiology, hydrobiology, ecology, hydraulics, hydrology, etc. In the process of solving the problem of standardization of information to be used for creating mathematical models for forecasting potential impact of water intakes with fish protection on aquatic ecosystem. The article gives a review of the research on the technology of aquatic bioresources (ABR) conservation, conducted by JSC «Institute Hydroproject» (Moscow) together with LLC «Hydrotechnika» (Sochi), the basic provisions of modeling methodology are considered; the results of mathematical modeling of currents in the upstream in the area of hydraulic units, spillways and rockfi ll dam at Boguchanskaya HPP; results of experimental studies of stream generators and biohydraulic modeling. The assessment of the conducted research is given.

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Wetter, Oliver. « The potential of historical hydrology in Switzerland ». Hydrology and Earth System Sciences 21, n^o 11 (23 novembre 2017) : 5781–803. http://dx.doi.org/10.5194/hess-21-5781-2017.

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Abstract. Historical hydrology is based on data derived from historical written, pictorial and epigraphic documentary sources. It lies at the interface between hydrology and environmental history, using methodologies from both disciplines basically with the goal of significantly extending the instrumental measurement period with experience from the pre-instrumental past. Recently this field of research has gained increased recognition as a tool to improve current flood risk estimations when EU guidelines regulated by law the quantitative consideration of previous floods.1 Awareness to consider pre-instrumental experience in flood risk analysis seems to have risen at the level of local and federal authorities in Switzerland as well. The 2011 Fukushima catastrophe probably fostered this rethinking process, when pressure from the media, society and politics as well as the regulations of the International Atomic Energy Agency (IAEA) forced the authorities to reassess the current flood risk analysis for Swiss nuclear power plants. In 2015 a historical hydrological study was commissioned by the Federal Office for the Environment (FOEN) to assess the magnitudes of pre-instrumental Aare River flood discharges, including the most important tributaries (the Saane, Emme, Reuss and Limmat rivers). The results of the historical hydrological study serve now as the basis for the main study, EXAR (commissioned under the lead of FOEN in cooperation with the Swiss Nuclear Safety Inspectorate (ENSI), the Swiss Federal Office of Energy (SFOE), the Federal Office for Civil Protection (FOCP), and the Federal Office of Meteorology and Climatology (MeteoSwiss)), which combines historical and climatological analysis with statistical approaches and mathematical models with the goal of better understanding the hazards and possible interactions that can be caused by extreme flood events. In a second phase the catchment of the River Rhine will be targeted as well. More recently several local historical hydrological studies of smaller catchments have been requested by the responsible local authorities. The course for further publicly requested historical hydrological analysis seems thus to have been set. This paper therefore intends to discuss the potential of historical hydrological analysis, with a focus on the specific situation in Switzerland. 1Guideline 2007/60/EG of the European Parliament and Council from 23 October 2007 on assessment and management of flood risks, Official Journal of the European Union, L 288, 27–34, Brussels, 2007.

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Shein, Ye V., A. G. Bolotov et A. V. Dembovetskii. « Soil Hydrology of Agricultural Landscapes : Quantitative Description, Research Methods, and Availability of Soil Water ». Eurasian Soil Science 54, n^o 9 (septembre 2021) : 1367–74. http://dx.doi.org/10.1134/s1064229321090076.

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Abstract Soil hydrology has deep Russian roots, which are primarily related to the theory of soil hydrological constants and their practical application. These constants have been used to assess the hydrological soil conditions in stationary observations, for which attempts to arrange regular hydrological observations in the landscape faced impracticable complexity of work and calculations and provided unreliable quantitative predictions. At present, there are new opportunities for experimental research, digital analysis, and prediction of hydrological indicators of soils in the landscape. A new quantitative approach to the use of digital technologies for monitoring soil water and temperature in the soils of agricultural landscapes, their dynamics, and their probabilistic calculations has been developed. Based on the soil map, it is proposed to create an information and measurement system with the studied thermal and hydrophysical characteristics of soils using mathematical models to calculate the dynamics of moisture and temperature for given periods and conditions of different availability of heat and precipitation, which allows us to quantify the availability of moisture reserves in the soils of the agricultural landscape. This system of observations, assessment, and forecast includes the use of modern technologies for determining soil water content and temperature, the adaptation of predictive physically based models for calculating the dynamics of moisture reserves depending on the availability of precipitation and conditions at the lower boundary of soil profiles. The paper deals with the hydrological analysis of soils by the example of the agricultural landscape of the Zelenograd station of the Dokuchaev Soil Science Institute in the village of El’digino, Pushkino district, Moscow oblast.

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Genuchten, Martinus Th van, Feike J. Leij, Todd H. Skaggs, Nobuo Toride, Scott A. Bradford et Elizabeth M. Pontedeiro. « Exact analytical solutions for contaminant transport in rivers 1. The equilibrium advection-dispersion equation ». Journal of Hydrology and Hydromechanics 61, n^o 2 (1 juin 2013) : 146–60. http://dx.doi.org/10.2478/johh-2013-0020.

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Abstract Analytical solutions of the advection-dispersion equation and related models are indispensable for predicting or analyzing contaminant transport processes in streams and rivers, as well as in other surface water bodies. Many useful analytical solutions originated in disciplines other than surface-water hydrology, are scattered across the literature, and not always well known. In this two-part series we provide a discussion of the advection-dispersion equation and related models for predicting concentration distributions as a function of time and distance, and compile in one place a large number of analytical solutions. In the current part 1 we present a series of one- and multi-dimensional solutions of the standard equilibrium advection-dispersion equation with and without terms accounting for zero-order production and first-order decay. The solutions may prove useful for simplified analyses of contaminant transport in surface water, and for mathematical verification of more comprehensive numerical transport models. Part 2 provides solutions for advective- dispersive transport with mass exchange into dead zones, diffusion in hyporheic zones, and consecutive decay chain reactions.

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Belvederesi, Chiara, Mohamed S. Zaghloul, Gopal Achari, Anil Gupta et Quazi K. Hassan. « Modelling river flow in cold and ungauged regions : a review of the purposes, methods, and challenges ». Environmental Reviews 30, n^o 1 (mars 2022) : 159–73. http://dx.doi.org/10.1139/er-2021-0043.

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River flow forecasting models assist in the understanding, predicting, monitoring, and managing of issues related to surface-water resources, such as water quality deterioration and flooding, or developing adaptation strategies to cope with climate change and increasing water demand. This review presents an overview of the current research status and progress in river-flow forecasting, focusing on cold climates and ungauged locations. River-flow forecasting in cold regions represents a challenge because the natural processes that occur within catchments vary greatly both seasonally and annually. This variability, which highly depends on climatic and topo-geomorphological characteristics within a basin, translates into increased model uncertainty and a substantial limitation when attempting to forecast river flow in cold regions, which are often poorly gauged or ungauged. To address this limitation, the “Predictions in Ungauged Basins” initiative offers a variety of studies to improve forecasting performance by adopting regionalization, spatial calibration, interpolation, and regression approaches. Process-based models demonstrate significant improvement by including remote-sensing data to replicate and derive complex hydrological processes. Empirical models, which utilize observed data to formulate a graphical solution, unlike mathematical models that require formulating the relationships between the processes, are also implemented with the most recent developments in machine learning, showing exceptional forecasting accuracy. Although process-based models provide a wide understanding of a watershed hydrology, data are often unavailable, expensive, and time-consuming to collect. They also generate numerous calibration parameters, resulting in complex and computationally demanding methods to operate. River-flow forecasting using empirical models reduces the number of calibration parameters but could produce biased results when insufficient variables are available to explain the physical mechanisms of a watershed’s hydrology. Moreover, empirical models could be potentially sensitive to calibration and validation dataset selection. In this review, Canadian studies are primarily selected to highlight some of the efforts that may be necessary in other similar cold and ungauged regions, including: (i) coping with limited data availability through regionalization methods; (ii) providing user-friendly interfaces; (iii) advancing model structure; (iv) developing a universal method for transferring regionalization parameters; (v) standardizing calibration and validation dataset selection; (vi) integrating process-based and empirical models.

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Rosso, R., M. C. Rulli et D. Bocchiola. « Transient catchment hydrology after wildfires in a Mediterranean basin : runoff, sediment and woody debris ». Hydrology and Earth System Sciences 11, n^o 1 (17 janvier 2007) : 125–40. http://dx.doi.org/10.5194/hess-11-125-2007.

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Abstract. The transient effect of forest fires on runoff, erosion and yield of woody biomass has been investigated by combining the experimental approach with mathematical models of hydrological processes. The case study is the Branega creek in Liguria, Italy, where a forest fire in August 2003 caused substantial changes to soil and vegetation, and left a considerable amount of woody debris on the ground. Immediately after the fire, rainfall simulator experiments in adjacent burned and unburned plots showed the extent to which fire had increased runoff and erosion rates. A distributed hydrological model using the tube-flux approach, calibrated on experimental measurements, has been used to investigate hill slope and channel erosion in a small sub-catchment, 1.5 ha in area, nested in the Branega basin. Simulation runs show that the model accommodates the observed variability of runoff and erosion under disturbed and undisturbed conditions. A model component describing the delivery of wood from hill slopes to the channel in post-fire conditions, validated against local survey data, showed that the removal and transport of woody biomass can be reproduced using an integrated hydrological approach. Hence, transient complexity after wildfires can be addressed by such an approach with empirically determined physically-based parameters.

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Dinu, Cristian, Radu Drobot, Claudiu Pricop et Tudor Viorel Blidaru. « Genetic Programming Technique Applied for Flash-Flood Modelling Using Radar Rainfall Estimates ». Mathematical Modelling in Civil Engineering 13, n^o 4 (20 décembre 2017) : 27–38. http://dx.doi.org/10.1515/mmce-2017-0012.

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AbstractThe rainfall-runoff transformation is a highly complex dynamic process and the development of fast and robust modelling instruments has always been one of the most important topics for hydrology. Over time, a significant number of hydrological models have been developed with a clear trend towards a process-based approach. The downside of these types of models is the significant amount of data required for building the model and for the calibration process: in practice, the collection of all necessary data for such models proves to be a difficult task. In order to cope with this issue, various data-driven modelling techniques have been introduced for hydrological modelling as an alternative to more traditional approaches, on the basis of their capacity of mapping out complex relationships from observation data. Having the capacity to generate meaningful mathematical structures as results, genetic programming (GP) presents a high potential for rainfall-runoff modelling as a data-driven method. Using ground and radar rainfall observation, the aim of this study is to investigate the GP technique capability for modelling the rainfall-runoff process, taking into consideration a flash-flood event.

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Abreu, Marcel Carvalho, Roberto Avelino Cecílio, Sidney Sara Zanetti et Cecília Neves Catrinck. « ESTIMATIVA DA PRECIPITAÇÃO NO ESPÍRITO SANTO POR INTERMÉDIO DE REGRESSÃO POLINOMIAL ». Nativa 7, n^o 2 (11 mars 2019) : 174. http://dx.doi.org/10.31413/nativa.v7i2.6169.

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A precipitação é um dos principais elementos da hidrologia, sendo uma variável de grande importância para a compreensão da dinâmica do ciclo hidrológico. Apesar da sua importância, a disponibilidade de dados hidroclimáticos é baixa. Dentre as alternativas para suprir a necessidade de informações da precipitação, a modelagem matemática é uma importante ferramenta que visa e sua estimativa. Assim, este trabalho avaliou as precipitações mensais e anuais de 110 estações pluviométricas do estado do Espírito Santo e avaliou o ajuste de modelos polinomiais de ordem 1 a 4 utilizando a longitude, latitude e altitude como variáveis explicativas para a previsão dessas precipitações. A precipitação no Espírito Santo mostrou variabilidade considerável, indicando grande influência do relevo, sendo observado também que localidades com maiores altitudes apresentaram maiores totais precipitados. A regressão polinomial de quarto grau se mostrou a mais adequada em representar as precipitações médias mensais e anual. Os ajustes foram considerados suficientes para representar as precipitações do Espírito Santo, com coeficientes de determinação superiores a 0,7 e erros percentuais absolutos médios entre 5,9% e 16,6%. Foi observada uma leve tendência dos modelos em subestimar os valores observados. De maneira geral, os meses do período seco, especialmente de maio a julho, obtiveram melhor desempenho dos modelos.Palavras-chave: modelagem matemática, climatologia, hidrologia, chuva. ESTIMATION OF PRECIPITATION IN THE ESPÍRITO SANTO STATE BY POLYNOMIAL REGRESSION ABSTRACT: Precipitation is one of the main elements of hydrology, being a variable of great importance for understanding the dynamics of the hydrological cycle. Despite their importance, the availability of hydroclimatic data is low. Among the alternatives to meet the need for precipitation information, mathematical modeling is an important tool that aims its estimate. This work evaluated the monthly and annual rainfall of 110 rainfall gauges in the state of Espírito Santo and evaluated the adjustment of polynomial models of order 1 to 4 using longitude, latitude and altitude as explanatory variables to predict these precipitations. Precipitation in Espírito Santo showed considerable variability, indicating great influence of the relief, being observed that location with higher altitudes presented higher precipitated totals. The fourth-degree polynomial regression proved to be the most adequate to represent the mean monthly and annual precipitations. The adjustments were considered sufficient to represent the Espírito Santo precipitation, with coefficients of determination higher than 0.7 and mean absolute percentage errors between 5.9% and 16.6%. A slight trend of the models was observed in underestimating the observed values. In general, the months of the dry period, especially from May to July, obtained better performance of the models.Keywords: mathematical modeling, climatology, hydrology, rainfall.

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Deumlich, D., A. Jha et G. Kirchner. « Comparing measurements, ⁷Be radiotracer technique and process-based erosion model for estimating short-term soil loss from cultivated land in Northern Germany ». Soil and Water Research 12, No. 3 (28 juin 2017) : 177–86. http://dx.doi.org/10.17221/124/2016-swr.

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Due to changing climate and irregular weather patterns, event-based soil loss and sediment yield have become important issues in the agricultural areas. Several mathematical models and prediction methodologies have been used to estimate event-based soil loss and soil redistribution based on soil types, land management, hydrology and local topography. The use of short-lived beryllium-7 as a means of estimating event-based soil erosion/deposition rates has become an alternative to the traditional soil loss measurement methods. A new erosion model taking into account the movement of 7Be in soils has been presented recently. In order to direct the attention to the potential offered by this technique (measurements and mathematical model), a two-year study was performed at the erosion plots in Müncheberg, Germany, and twelve individual erosion rates were estimated. This paper presents a systematic comparison of the non-steady state 7Be model with the process-based erosion model EROSION-3D and measured data. The results demonstrate a close consistency between the erosion rates estimated by erosion models and the estimates provided by the 7Be model and can therefore be seen as a promising contribution to validating the use of this radionuclide to document short-term soil redistribution within the plot and deposited sediment at the bottom of the plot.

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Gautam, Narayan Prasad. « Flow routing with Semi-distributed hydrological model HEC- HMS in case of Narayani River Basin ». Journal of the Institute of Engineering 10, n^o 1 (31 juillet 2014) : 45–58. http://dx.doi.org/10.3126/jie.v10i1.10877.

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Routing is the modeling process to determine the outflow at an outlet from given inflow at upstream of the channel. A hydrological simulation model use mathematical equations that establish relationships between inputs and outputs of water system and simulates the catchment response to the rainfall input. Several hydrological models have been developed to assist in understanding of hydrologic system and water resources management. A model, once calibrated and verified on catchments, provides a multi-purpose tool for further analysis. Semi-Distributed models in hydrology are usually physically based in that they are defined in terms of theoretically acceptable continuum equations. They do, however, involve some degree of lumping since analytical solutions to the equations cannot be found, and so approximate numerical solutions, based on a finite difference or finite element discretization of the space and time dimensions, are implemented. Many rivers in Nepal are either ungauged or poorly gauged due to extreme complex terrains, monsoon climate and lack of technical and financial supports. In this context the role of hydrological models are extremely useful. In practical applications, hydrological routing methods are relatively simple to implement reasonably accurate. In this study, Gandaki river basin was taken for the study area. Kinematic wave method was used for overland routing and Muskingum cunge method was applied for channel routing to describe the discharge on Narayani river and peak flow attenuation and dispersion observed in the direct runoff hydrograph. Channel cross section parameters are extracted using HEC- GeoRAS extension tool of GIS. From this study result, Annual runoff, Peak flow and time of peak at the outlet are similar to the observed flow in calibration and verification period using trapezoidal channel. Hence Hydrological modeling is a powerful technique in the planning and development of integrated approach for management of water resources. DOI: http://dx.doi.org/10.3126/jie.v10i1.10877Journal of the Institute of Engineering, Vol. 10, No. 1, 2014 pp. 45-58

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James, William, et Boregowda Shivalingaiah. « Storm water pollution modelling : buildup of dust and dirt on surfaces subject to runoff ». Canadian Journal of Civil Engineering 12, n^o 4 (1 décembre 1985) : 906–15. http://dx.doi.org/10.1139/l85-103.

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Many runoff models are currently in use to predict both the quantity and quality of storm water runoff. In most models, the quality algorithms need further development to gain the confidence of model users. The writers have attempted to disaggregate the accumulation process and to develop improved algorithms for pollutant buildup. The factors and processes that affect buildup include atmospheric dustfall due to plumes of dust-laden air, wind effects, vehicles, intentional removals (e.g., street cleaning), special activities (such as construction and demolition), biological decomposition, and population-related activities (e.g., vegetation density, insecticides, herbicides, fertilizers, and lawn cutting). Mathematical expressions for each of these mechanisms are presented and utilized to develop algorithms in the RUNOFF module of the SWMM3 package.A separate multiregression model is used to generate atmospheric dustfall from meteorological information; this is input to the new program (NEWBLD) to calculate pollutant accumulation on individual subcatchments. NEWBLD is interfaced with the RUNOFF block of SWMM3. A sensitivity analysis is carried out using data for the Chedoke Creek catchment in Hamilton, Ontario. The modified version of the SWMM3 RUNOFF block developed herein by incorporating the new water quality algorithms is called CHGQUAL. It is applied to an urban catchment in Hamilton, Ontario. Key words: storm water models, dust and dirt buildup, storm water pollution, urban hydrology, air pollution.

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Zhu, D., et I. D. Cluckie. « A preliminary appraisal of Thurnham dual polarisation radar in the context of hydrological modelling structure ». Hydrology Research 43, n^o 5 (3 mai 2012) : 736–52. http://dx.doi.org/10.2166/nh.2012.023.

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The Thurnham radar is a prototype of a potential operational C-Band dual-polarisation weather radar designed specifically for the measurement of rainfall. It is also designed to increase the radar coverage over London when operating as a conventional C-Band radar as a direct consequence of the Lewes floods of October 2000. Dual-polarisation processing is expected to provide improved estimation of rainfall rates, especially at higher intensities, in terms of clutter removal, attenuation correction and rainfall estimation. In this study, three hydrological models with different mathematical structures were selected to evaluate the impact that dual-polarisation technology could have on operational hydrology and recommendations provided on the further development of the dual-polarisation algorithms in the short term. The preliminary appraisal was focused on the Upper Medway Catchment (south of London, UK) using different precipitation inputs, including raingauge measurements, radar rainfall estimates from single-polarised algorithms (cartesian format) and five different dual-polarisation algorithms (polar format). The influence of the different rainfall inputs on the various hydrological models were compared using a extreme flood event to provide an initial evaluation of the performance of the Thurnham radar. Recommendations for applying dual-polarisation radar to real-time flood forecasting are discussed in detail.

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Iqbal, Muhammad Zafar, Muhammad Zeshan Arshad, Gamze Özel et Oluwafemi Samson Balogun. « A better approach to discuss medical science and engineering data with a modified Lehmann Type – II model ». F1000Research 10 (17 août 2021) : 823. http://dx.doi.org/10.12688/f1000research.54305.1.

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Background: Modeling with the complex random phenomena that are frequently observed in reliability engineering, hydrology, ecology, medical science, and agricultural sciences was once thought to be an enigma. Scientists and practitioners agree that an appropriate but simple model is the best choice for this investigation. To address these issues, scientists have previously discussed a variety of bounded and unbounded, simple to complex lifetime models. Methods: We discussed a modified Lehmann type II (ML-II) model as a better approach to modeling bathtub-shaped and asymmetric random phenomena. A number of complementary mathematical and reliability measures were developed and discussed. Furthermore, explicit expressions for the moments, quantile function, and order statistics were developed. Then, we discussed the various shapes of the density and reliability functions over various model parameter choices. The maximum likelihood estimation (MLE) method was used to estimate the unknown model parameters, and a simulation study was carried out to evaluate the MLEs' asymptotic behavior. Results: We demonstrated ML- II's dominance over well-known competitors by modeling anxiety in women and electronic data.

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Sebayang, Ika Sari Damayanthi, et Muhammad Fahmia. « Dependable flow modeling in upper basin Citarum using multilayer perceptron backpropagation ». International Journal of Artificial Intelligence Research 4, n^o 2 (5 janvier 2021) : 75. http://dx.doi.org/10.29099/ijair.v4i2.174.

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To determine the amount of dependable flow, a hydrological approach is needed where changes in rainfall become runoff. This diversification is a very complex hydrological phenomenon. Where this is a nonlinear process, with time changing and distributed separately. To approach this phenomenon, an analysis of the hydrological system has been developed using a model which is a simplification of the actual natural variables. The model is formed by a set of mathematical equations that reflect the behavior of parameters in hydrology. Modeling in this case uses artificial neural networks, multilayer perceptron combined with the backpropagation method is used to study the rainfall-runoff relationship and verify the model statistically based on the mean square error (MSE), Nash-Sutcliffe Efficiency (NSE) and correlation coefficient value (R2). Of the three models formed, model 3 provides optimum results with correlation levels using NSE per month as follows, in Cikapundung Sub-Basin NSE = 0,990703, R2 = 0,995008, and MSE = 0,00014443, while in Citarik Sub-Basin NSE = 0.9500, R2 = 0.97592, and MSE = 0.0010804 . From these results it can be seen that ANN has a fairly good ability to replicate random discharge fluctuations in the form of artificial models that have almost the same fluctuations and can also be applied in rainfall runoff modelization even though the results of the test results are not very accurate because there are still irregularities

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Macías Barberán, José Ricardo, Gerardo José Cuenca Nevárez, Frank Guillermo Intriago Flor, Creuci Maria Caetano, Juan Carlos Menjivar Flores et Henry Antonio Pacheco Gil. « Vulnerability to climate change of smallholder cocoa producers in the province of Manabí, Ecuador ». Revista Facultad Nacional de Agronomía Medellín 72, n^o 1 (1 janvier 2019) : 8707–16. http://dx.doi.org/10.15446/rfnam.v72n1.72564.

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The consequences of climate change in the agricultural sector worldwide expose the need to understand the scope of their impact in order to develop mitigation and adaptation strategies for them. Therefore, this research evaluated the alterations in the environmental conditions and their relation with the vulnerability of smallholder cocoa (Theobroma cacao L.) producers to climate change in the province of Manabí. A non-probabilistic sampling of 1,060 small farmers was made in five cantons of Manabí. The vulnerability was determined through indicators such as the normalized difference vegetation index (NDVI), deforestation data from 1990 to 2016, models of the changes in climate and extreme weather events, satellite images, records from the National Institute of Meteorology and Hydrology (INAMHI by its initials in Spanish), and numerical outputs of mathematical models calibrated for Ecuador climatic and environmental data. Each indicator was calculated in conventional units and then categorized into vulnerability levels: low, medium, high and very high. For the indicators’ superposition, algebraic tools of the Geographic Information Systems’ (GIS) maps were used. The results showed a very high incidence of extreme events, deforestation higher than 6,000 ha year-1, an increase of 0.8 °C in temperature between 1960 and 2006, an increase in rainfall on the coastal zone close to 90% and a decrease of it of more than 20% on the agricultural area. Furthermore, coverage showed the following distribution of the determined vulnerability levels: low (13.30%), medium (34.74%), high (45.53%), and very high (6.43%).

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Livingstone, Stephen J., Emma L. M. Lewington, Chris D. Clark, Robert D. Storrar, Andrew J. Sole, Isabelle McMartin, Nico Dewald et Felix Ng. « A quasi-annual record of time-transgressive esker formation : implications for ice-sheet reconstruction and subglacial hydrology ». Cryosphere 14, n^o 6 (18 juin 2020) : 1989–2004. http://dx.doi.org/10.5194/tc-14-1989-2020.

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Abstract. We identify and map chains of esker beads (series of aligned mounds) up to 15 m high and on average ∼ 65 m wide in central Nunavut, Canada, from the high-resolution (2 m) ArcticDEM. Based on the close 1 : 1 association with regularly spaced, sharp-crested ridges interpreted as De Geer moraines, we interpret the esker beads to be quasi-annual ice-marginal deposits formed time-transgressively at the mouth of subglacial conduits during deglaciation. Esker beads therefore preserve a high-resolution record of ice-margin retreat and subglacial hydrology. The well-organised beaded esker network implies that subglacial channelised drainage was relatively fixed in space and through time. Downstream esker bead spacing constrains the typical pace of deglaciation in central Nunavut between 8.1 and 6.8 cal kyr BP to 165–370 m yr−1, although with short periods of more rapid retreat (> 400 m yr−1). Under our time-transgressive interpretation, the lateral spacing of the observed eskers provides a true measure of subglacial conduit spacing for testing mathematical models of subglacial hydrology. Esker beads also record the volume of sediment deposited from conduits in each melt season, thus providing a minimum bound on annual sediment fluxes, which is in the range of 103–104 m3 yr−1 in each 6–10 km wide subglacial conduit catchment. We suggest that the prevalence of esker beads across this predominantly marine-terminating sector of the Laurentide Ice Sheet is a result of sediment fluxes that were unable to backfill conduits at a rate faster than ice-margin retreat. Conversely, we hypothesise that esker ridges form when sediment backfilling of the subglacial conduit outpaced retreat, resulting in headward esker growth close to but behind the margin. The implication, in accordance with recent modelling results, is that eskers in general record a composite signature of ice-marginal drainage rather than a temporal snapshot of ice-sheet-wide subglacial drainage.

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Abdulai, Patricia Jitta, et Eun-Sung Chung. « Uncertainty Assessment in Drought Severities for the Cheongmicheon Watershed Using Multiple GCMs and the Reliability Ensemble Averaging Method ». Sustainability 11, n^o 16 (8 août 2019) : 4283. http://dx.doi.org/10.3390/su11164283.

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The consequence of climate variations on hydrology remains the greatest challenging aspect of managing water resources. This research focused on the quantitative approach of the uncertainty in variations of climate influence on drought pattern of the Cheongmicheon watershed by assigning weights to General Circulation Models (GCMs) based on model performances. Three drought indices, Standardized Precipitation Evapotranspiration Index (SPEI), Standardized Precipitation Index (SPI) and Streamflow Drought Index (SDI) are used for three durations 3-, 6- and 9-months. This study included 27 GCMs from Coupled Model Intercomparison Project 5 (CMIP5) and considered three future periods (2011–2040, 2041–2070 and 2071–2100) of the concentration scenario of Representation Concentration Pathway (RCP) 4.5. Compared to SPEI and SDI, SPI identified more droughts in severe or extreme categories of shorter time scales than SPEI or SDI. The results suggested that the discrepancy in temperature plays a significant part in characterizing droughts. The Reliability Ensemble Averaging (REA) technique was used to give a mathematical approximation of associated uncertainty range and reliability of future climate change predictions. The uncertainty range and reliability of Root Mean Square Error (RMSE) varied among GCMs and total uncertainty ranges were between 50% and 200%. This study provides the approach for realistic projections by incorporating model performance ensemble averaging based on weights from RMSE.

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Simmonds, Jose, Juan A. Gómez et Agapito Ledezma. « The role of agent-based modeling and multi-agent systems in flood-based hydrological problems : a brief review ». Journal of Water and Climate Change 11, n^o 4 (25 octobre 2019) : 1580–602. http://dx.doi.org/10.2166/wcc.2019.108.

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Abstract Flood problems are complex phenomena with a direct relationship with the hydrological cycle; these are natural processes occurring in water systems, that interact at different spatial and temporal scales. In modeling the hydrological phenomena, traditional approaches, like physics-based mathematical equations and data-driven modeling (DDM) are used. Advances in hydroinformatics are helping to understand these physical processes, with improvements in the collection and analysis of hydrological data, information and communication technologies (ICT), and geographic information systems (GIS), offering opportunities for innovations in model implementation, to improve decision support for the response to societally important floods impacting our societies. This paper offers a brief review of agent-based models (ABMs) and multi-agent systems (MASs) methodologies' applications for solutions to flood problems, their management, assessment, and efforts for forecasting stream flow and flood events. Significant observations from this review include: (i) contributions of agent technologies, as a growing methodology in hydrology; (ii) limitations; (iii) capabilities of dealing with distributed and complex domains; and (iv), the capabilities of MAS as an increasingly accepted point of view applied to flood modeling, with examples presented to show the variety of system combinations that are practical on a specialized architectural level for developing and deploying sophisticated flood forecasting systems.

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Chan, T. P., et Rao S. Govindaraju. « Pore-morphology-based simulations of drainage and wetting processes in porous media ». Hydrology Research 42, n^o 2-3 (1 avril 2011) : 128–49. http://dx.doi.org/10.2166/nh.2011.058.

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Soil hydraulic properties relating saturation, water pressure, and hydraulic conductivity are known to exhibit hysteresis. In this paper, we focus on the determination of the water retention curve for a porous medium through a novel pore-scale simulation technique that is based on mathematical morphology. We develop an algorithm that allows for the representation of three-dimensional randomly packed porous media of any geometry (i.e. not restricted to idealized geometries such as spherical or ellipsoidal particles/pore space) so that the connectivity-, tortuosity-, and hysteresis-causing mechanisms are represented in both drainage and wetting processes, and their role in determining macroscopic fluid behavior is made explicit. Using this method, we present simulation results that demonstrate hysteretic behavior of wetting and non-wetting phases during both drainage and wetting cycles. A new method for computing interfacial surface areas is developed. The pore-morphology-based method is critically evaluated for accuracy, sample size effects, and resolution effects. It is found that the method computes interfacial areas more accurately than existing methods and allows for (i) examination of relationships between water pressure, saturation and interfacial area for hysteretic soils, and (ii) comparisons with previously developed theoretical models of soil hydraulic properties. The pore-morphology-based method shows promise for applications in vadose zone hydrology.

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Lundström, T., Hans Åkerstedt, I. Larsson, Jiri Marsalek et Maria Viklander. « Dynamic Distributed Storage of Stormwater in Sponge-Like Porous Bodies : Modelling Water Uptake ». Water 12, n^o 8 (22 juillet 2020) : 2080. http://dx.doi.org/10.3390/w12082080.

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An innovative concept of dynamic stormwater storage in sponge-like porous bodies (SPBs) is presented and modelled using first principles, for down-flow and up-flow variants of SPBs. The rate of inflow driven by absorption and/or capillary action into various porous material structures was computed as a function of time and found to be critically dependent on the type of structure and the porous material used. In a case study, the rates of inflow and storage filling were modelled for various conditions and found to match, or exceed, the rates of rainwater inflow and volume accumulation associated with two types of Swedish rainfalls, of 60-min duration and a return period of 10 years. Hence, the mathematical models indicated that the SPB devices studied could capture relevant amounts of water. The theoretical study also showed that the SPB concepts could be further optimized. Such findings confirmed the potential of dynamic SPB storage to control stormwater runoff and serve as one of numerous elements contributing to restoration of pre-urban hydrology in urban catchments. Finally, the issues to be considered in bringing this theoretical concept to a higher Technological Readiness Level were discussed briefly, including operational challenges. However, it should be noted that a proper analysis of such issues requires a separate study building on the current presentation of theoretical concepts.

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Balogun, Oluwafemi Samson, Muhammad Zeshan Arshad, Muhammad Zafar Iqbal et Madiha Ghamkhar. « A new modified Lehmann type – II G class of distributions : exponential distribution with theory, simulation, and applications to engineering sector ». F1000Research 10 (17 juin 2021) : 483. http://dx.doi.org/10.12688/f1000research.52494.1.

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Background: Modeling against non-normal data a challenge for theoretical and applied scientists to choose a lifetime model and expect to perform optimally against experimental, reliability engineering, hydrology, ecology, and agriculture sciences, phenomena. Method: We have introduced a new G class that generates relatively more flexible models to its baseline and we refer to it as the new modified Lehmann Type – II (ML–II) G class of distributions. A list of new members of ML–II-G class is developed and as a sub-model the exponential distribution, known as the ML-II-Exp distribution is considered for further discussion. Several mathematical and reliability characters along with explicit expressions for moments, quantile function, and order statistics are derived and discussed in detail. Furthermore, plots of density and hazard rate functions are sketched out over the certain choices of the parametric values. For the estimation of the model parameters, we utilized the method of maximum likelihood estimation. Results: The applicability of the ML–II–G class is evaluated via ML–II–Exp distribution. ML–II–Exp distribution is modeled to four suitable lifetime datasets and the results are compared with the well-known competing models. Some well recognized goodness–of–fit including -Log-likelihood (-LL), Anderson-Darling (A*), Cramer-Von Mises (W*), and Kolmogorov-Smirnov (K-S) test statistics are considered for the selection of a better fit model. Conclusion: The minimum value of the goodness–of–fit is the criteria of a better fit model that the ML–II–Exp distribution perfectly satisfies. Hence, we affirm that the ML–II–Exp distribution is a better fit model than its competitors.

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Lee, Kun-Fa, et Jia-Qi Lai. « Research on Modeling Technology and Application of Simulation Planning Based on Urban Ecological Park ». International Journal of Engineering and Technology 12, n^o 3 (août 2020) : 37–40. http://dx.doi.org/10.7763/ijet.2020.v12.1181.

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Based on the importance of the construction of the regional environmental space of the urban ecological park, research on the topography, geology, hydrology, human activities and other aspects of the ecological engineering area of the park, use Geographic Information System (GIS) and MIKE21 technology to construct the regional environmental space of the urban ecological park, and establish the urban park Eco-engineering river section plane two-dimensional water flow, mathematical model analysis provides predictive engineering, simulating the change characteristics of river flow field and water level under typical flow, and the regional environment of urban ecological park can be used as a construction to ensure the safety of flood discharge and the water level along the line under the flood stability. To study the impact of urban ecological park project flood control on the flow pattern of water. Excessive water velocity can easily cause serious damage to the river embankment, which affects the structural stability of the river embankment of the ecological park and ultimately affects the flood discharge capacity of the ecological park’s rivers. MIKE21 and ecological models are adopted. Analyze the feasibility of the modeling method by numerical simulation, establish the numerical simulation model of the urban ecological park, simulate the ecological regional modeling logic system, predict and analyze the impact of the project on the change of the flood carrying capacity of the river, and provide the engineering research of the urban ecological park.

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Tang, Jinyun, William J. Riley et Qing Zhu. « Supporting hierarchical soil biogeochemical modeling : version 2 of the Biogeochemical Transport and Reaction model (BeTR-v2) ». Geoscientific Model Development 15, n^o 4 (24 février 2022) : 1619–32. http://dx.doi.org/10.5194/gmd-15-1619-2022.

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Abstract. Reliable soil biogeochemical modeling is a prerequisite for credible projections of climate change and associated ecosystem feedbacks. This recognition has called for frameworks that can support flexible and efficient development and application of new or alternative soil biogeochemical modules in Earth system models (ESMs). The the Biogeochemical Transport and Reaction model version 1 (BeTR-v1) code (i.e., CLM4-BeTR) is one such framework designed to accelerate the development and integration of new soil biogeochemistry formulations into ESMs and to analyze structural uncertainty in ESM simulations. With a generic reactive transport capability, BeTR-v1 can represent multiphase (e.g., gaseous, aqueous, and solid), multi-tracer (e.g., nitrate and organic carbon), and multi-organism (e.g., plants, bacteria, and fungi) dynamics. Here, we describe the new version, Biogeochemical Transport and Reaction model version 2 (BeTR-v2), which adopts more robust numerical solvers for multiphase diffusion and advection and coupling between biogeochemical reactions and improves code modularization over BeTR-v1. BeTR-v2 better supports different mathematical formulations in a hierarchical manner by allowing the resultant model be run for a single topsoil layer or a vertically resolved soil column, and it allows the model to be fully coupled with the land component of the Energy Exascale Earth System Model (E3SM). We demonstrate the capability of BeTR-v2 with benchmark cases and example soil biogeochemical (BGC) implementations. By taking advantage of BeTR-v2's generic structure integrated in E3SM, we then found that calibration could not resolve biases introduced by different numerical coupling strategies of plant–soil biogeochemistry. These results highlight the importance of numerically robust implementation of soil biogeochemistry and coupling with hydrology, thermal dynamics, and plants – capabilities that the open-source BeTR-v2 provides. We contend that Earth system models should strive to minimize this uncertainty by applying better numerical solvers.

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Stefanyshyn, Dmytro V., Yaroslaw V. Khodnevich et Vasyl M. Korbutiak. « Еstimating the Chézy roughness coefficient as a characteristic of hydraulic resistance to flow in river channels : a general overview, existing challenges, and ways of their overcoming ». Environmental safety and natural resources 39, n^o 3 (23 septembre 2021) : 16–43. http://dx.doi.org/10.32347/2411-4049.2021.3.16-43.

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This paper deals with results of a systemized overview of the Chézy roughness coefficient calculation problem as one most frequently used empirical characteristics of hydraulic resistance. The overview is given in the context of the formation of reliable empirical data needed to support hydro-engineering calculations and mathematical modelling of open flows in river channels. The problem topicality is because of a large number of practical tasks which need such a pre-research. In many cases, the accuracy of determining empirical hydraulic resistance characteristics can largely affect the accuracy of solving tasks relating to designing hydraulic structures and water management regardless of chosen mathematical models and methods.Rivers are characterized by a significant variety of flow conditions; hydraulic resistance to flows in rivers can thus vary widely determining their flow capacity. Considering the variety of river hydro-morphology and hydrology, the Chézy roughness coefficient often appears to be the most complete characteristic of hydraulic resistance to open flows in river channels comparing with other integral empirical characteristics of hydraulic resistance.At present, there are a large number of empirical and semi-empirical formulas to calculate the Chézy roughness coefficient. The main aim of this study was to analyze and systematize them in the context of providing proper support to the open channel hydraulics tasks. To achieve the aim of the study, a literature review regarding the problem of determining the integral hydraulic resistance characteristics to open flow in river channels was performed, as well as formulas used to calculate the Chézy roughness coefficient in practice were explored and systemized. In total, 43 formulas to calculate the Chézy roughness coefficient, as well as 13 formulas that can be used to estimate the Manning roughness coefficient were analyzed and systematized. Based on all these formulas, about 250 empirical equations can be compiled to calculate the Chézy coefficient depending on hydro-morphological peculiarities of rivers and river channels, hydraulic conditions, formulas application limits, and so on.

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Goldsmith, W., D. Bernardi et L. Schippa. « River, delta and coastal morphological response accounting for biological dynamics ». Proceedings of the International Association of Hydrological Sciences 367 (3 mars 2015) : 413–20. http://dx.doi.org/10.5194/piahs-367-413-2015.

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Abstract. Management and construction can increase resilience in the face of climate change, and benefits can be enhanced through integration of biogenic materials including shells and vegetation. Rivers and coastal landforms are dynamic systems that respond to intentional and unintended manipulation of critical factors, often with unforeseen and/or undesirable resulting effects. River management strategies have impacts that include deltas and coastal areas which are increasingly vulnerable to climate change with reference to sea level rise and storm intensity. Whereas conventional assessment and analysis of rivers and coasts has relied on modelling of hydrology, hydraulics and sediment transport, incorporating additional biological factors can offer more comprehensive, beneficial and realistic alternatives. Suitable modelling tools can provide improved decision support. The question has been whether current models can effectively address biological responses with suitable reliability and efficiency. Since morphodynamic evolution exhibits its effects on a large timescale, the choice of mathematical model is not trivial and depends upon the availability of data, as well as the spatial extent, timelines and computation effort desired. The ultimate goal of the work is to set up a conveniently simplified river morphodynamic model, coupled with a biological dynamics plant population model able to predict the long-term evolution of large alluvial river systems managed through bioengineering. This paper presents the first step of the work related to the application of the model accounting for stationary vegetation condition. Sensitivity analysis has been performed on the main hydraulic, sedimentology, and biological parameters. The model has been applied to significant river training in Europe, Asia and North America, and comparative analysis has been used to validate analytical solutions. Data gaps and further areas for investigation are identified.

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Cabezas Pinzón, Laura Viviana, Rigaud Sanabria-Marin, Federico Andrade-Rivas, Aquiles Darghan et Víctor-Alberto Olano. « Relation between Environmental Variables and the Spatial Distribution of the Aedes aegypti Mosquito in Rural Colombia ». Revista Salud Bosque 12, n^o 1 (25 avril 2022) : 1–18. http://dx.doi.org/10.18270/rsb.v12i1.3218.

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Background: Changes in global and local environmental variables condition the distribution and density of disease vectors. This study aimed to estimate the relationship between the entomological indicator of immature and adult forms of the Aedes aegypti mosquito per unit area, the environmental variables of temperature, precipitation, and relative humidity in rural areas of two municipalities in Colombia. Methods: Four spatial regression models were fitted: The Spatial Autoregressive Model with Autoregressive Disturbances of order [1,1] (SARAR[1,1]), Spatial Error Model (SEM), Spatial Lag Model (SLM), and the Pure Spatial Autoregressive Model. Immature and adult A. aegypti forms were collected in homes during June 2013 (dry season). The houses were chosen at random and were georeferenced. Climate information was obtained from the Institute of Hydrology, Meteorology and Environmental Studies (IDEAM- Instituto de Hidrología, Meteorología y Estudios Ambientales). Climatic information was completed with mathematical interpolation from the Akima library. Results: The most appropriate model was SARAR[1,1], as it showed the lowest values of the Akaike information criterion (AIC = 473.34). In this model, the variable that best explained the entomological indicator (immature and adult forms per unit area) was the altitude of the houses in the rural area where the entomological samples were collected. This means that the higher the altitude, the lower the entomological indicator calculated. The ranges of the environmental variables in which the presence of the mosquito occurred are between 602 to 1414 m.a.s.l (meters above sea level) for altitude, 17 °C to 27 °C for temperature, 27 mm to 86 mm for precipitation, and 70% to 85% for relative humidity. Conclusions: The importance of understanding the relationship between local environmental characteristics and the presence of the vector for designing comprehensive management strategies was highlighted, contributing to better surveillance, prevention, and control of vectors and diseases transmitted by them.

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Rathi, Vinay Kumar, Shobha Ram, Rohitashw Kumar, Avinash Agarwal et R. K. Nema. « Hydrological classification and performance of Himalayan springs in climate change scenario – a case study ». Water Supply 20, n^o 2 (27 décembre 2019) : 594–608. http://dx.doi.org/10.2166/ws.2019.191.

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Abstract The present study was conducted to evaluate 33 springs' hydrology (discharge and yield estimation) of Chandrabhaga and Danda watersheds of Uttarakhand, India. The springs were classified using Meinzer method and evaluated the relative performance for rejuvenation strategy. It was found that most of springs fall in sixth and seventh class order with flow rate 6.5 to 65.5 and 0.8 to 6.5 m3·day−1, respectively. The relative performance of springs were analyzed based on four methods: (i) spring flow variability, (ii) normalized spring flow (short and long duration), (iii) rainfall spring flow lag and (iv) spring flow gradient. The relative results of springs were analyzed on a scale of 0–5. The Chandrabhaga springs 01, 03, 4B, 05, 06 and 13 were found to be relatively good on a scale value of 4 out of 5 as compared to springs 4A, 07, and 10A with a scale value of 1. For the Danda watershed, the relative performance of springs 4A and 28 found on scale value of 5 and springs 4B, 11 and 20 with a scale value of 4 are relatively good compared to springs 02, 06, 07, 15 and 17. The cumulative flow of spring showed a linear response with cumulative rainfall for the period of June to September (monsoon period). The spring-shed was delineated and evaluated for optimization for the maximum efficiency, spring flow, ratio of area and relief versus maximum spring flow yield. The results revealed that the quantification of water fluxes for water balances, storage of groundwater and development of mathematical models can be used for sustainable water resources development and to revive the mountain springs which helped the adverse impacts of climate change.

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Dong, Leihua, Lihua Xiong et Kun-xia Yu. « Uncertainty Analysis of Multiple Hydrologic Models Using the Bayesian Model Averaging Method ». Journal of Applied Mathematics 2013 (2013) : 1–11. http://dx.doi.org/10.1155/2013/346045.

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Since Bayesian Model Averaging (BMA) method can combine the forecasts of different models together to generate a new one which is expected to be better than any individual model’s forecast, it has been widely used in hydrology for ensemble hydrologic prediction. Previous studies of the BMA mostly focused on the comparison of the BMA mean prediction with each individual model’s prediction. As BMA has the ability to provide a statistical distribution of the quantity to be forecasted, the research focus in this study is shifted onto the comparison of the prediction uncertainty interval generated by BMA with that of each individual model under two different BMA combination schemes. In the first BMA scheme, three models under the same Nash-Sutcliffe efficiency objective function are, respectively, calibrated, thus providing three-member predictions ensemble for the BMA combination. In the second BMA scheme, all three models are, respectively, calibrated under three different objective functions other than Nash-Sutcliffe efficiency to obtain nine-member predictions ensemble. Finally, the model efficiency and the uncertainty intervals of each individual model and two BMA combination schemes are assessed and compared.

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Cárdenas Gutiérrez, Javier Alfonso, Jose Leonardo Jacome Carrascal et Mawency Vergel Ortega. « Determination of potential and actual evapotranspiration in watershed, using mathematical models ». Revista Boletín Redipe 10, n^o 3 (1 mars 2021) : 225–31. http://dx.doi.org/10.36260/rbr.v10i3.1230.

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In this research, it is analyzed the calculation of real evapotranspiration in hydrographic basins, it is taken as a reference the Aguablanca Creek, located in the municipality of Bochalema, North of Santander-Colombia, where it is evaluated the hydrologic balance of this basin from the determination of detailed calculations of four mathematical models, to later evaluate the hydrologic balance of this basin, with the purpose of being able to make a better administration of these resources, as well as the use of the soil, betting on the development of an ecologically sustainable society with low environmental impact. The values of potential and real evapotranspiration, according to the most optimal model ETP Thorwaite 874 mm/year ETR 43712 mm/year, Cenicafe 712.81 mm/year ETR 612.1 mm/year Turc ETR 884.83 mm/year quota ETR 825 mm/year.

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Shu, Lele, Paul A. Ullrich et Christopher J. Duffy. « Simulator for Hydrologic Unstructured Domains (SHUD v1.0) : numerical modeling of watershed hydrology with the finite volume method ». Geoscientific Model Development 13, n^o 6 (18 juin 2020) : 2743–62. http://dx.doi.org/10.5194/gmd-13-2743-2020.

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Abstract. Hydrologic modeling is an essential strategy for understanding and predicting natural flows, particularly where observations are lacking in either space or time or where complex terrain leads to a disconnect in the characteristic time and space scales of overland and groundwater flow. However, significant difficulties remain for the development of efficient and extensible modeling systems that operate robustly across complex regions. This paper introduces the Simulator for Hydrologic Unstructured Domains (SHUD), an integrated, multiprocess, multiscale, flexible-time-step model, in which hydrologic processes are fully coupled using the finite volume method. SHUD integrates overland flow, snow accumulation/melt, evapotranspiration, subsurface flow, groundwater flow, and river routing, thus allowing physical processes in general watersheds to be realistically captured. SHUD incorporates one-dimensional unsaturated flow, two-dimensional groundwater flow, and a fully connected river channel network with hillslopes supporting overland flow and baseflow. The paper introduces the design of SHUD, from the conceptual and mathematical description of hydrologic processes in a watershed to the model's computational structures. To demonstrate and validate the model performance, we employ three hydrologic experiments: the V-catchment experiment, Vauclin's experiment, and a model study of the Cache Creek Watershed in northern California. Ongoing applications of the SHUD model include hydrologic analyses of hillslope to regional scales (1 m2 to 106 km2), water resource and stormwater management, and interdisciplinary research for questions in limnology, agriculture, geochemistry, geomorphology, water quality, ecology, climate and land-use change. The strength of SHUD is its flexibility as a scientific and resource evaluation tool where modeling and simulation are required.

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VERGARA, FERNÁN, VIVIANE CHIESA, CECILIA COSTA, ROBERTA OLIVEIRA, RICARDO DIAS et GIRLENE MACIEL. « Aplicabilidade do modelo matemático SAD-IPH na análise de processos de outorga : o caso da Bacia do Ribeirão Taquaruçu ». GOT - Journal of Geography and Spatial Planning, n^o 21 (30 juin 2021) : 208–34. http://dx.doi.org/10.17127/got/2021.21.009.

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In order to issue a water permit, which allows abstraction of water in a given place, the issuer needs to make sure, based on the hydrology of the region, that the amount of water available in the water body is sufficient to meet not only the demand associated with the required entitlement, but also all the existing demands from other users in the basin. This paper aims at evaluating the usefulness of the SAD-IPH mathematical model to simulate water demand scenarios in the Ribeirão Taquaruçu basin, located in the city of Palmas, state of Tocantins. Simulations provided by the SAD-IPH model indicate that the balance between water availability and demand is already critical in some parts of the basin, especially during the dry season, and the situation worsens over time. These results clearly suggest the local water utility needs to search for new water sources to meet the growing demand, mainly during the dry season. Results show the mathematical tool used in the analysis provides new and valuable information to decision makers (water resources institutions and river basin committees), potentially reducing the risk of making bad decisions. Additionally, as a water security measure, it is crucial to enforce the preservation of sensitive areas in the watershed because there is already an intense occupation in preserved areas next to water sources, a process that is likely to result in water yield reduction, which combined with an increase in the water demand over time, will compromise water security.

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D. K. Borah et M. Bera. « WATERSHED-SCALE HYDROLOGIC AND NONPOINT-SOURCE POLLUTION MODELS : REVIEW OF MATHEMATICAL BASES ». Transactions of the ASAE 46, n^o 6 (2003) : 1553–66. http://dx.doi.org/10.13031/2013.15644.

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Pawitan, Hidayat, et Muh Taufik. « Non-linear Routing Scheme at Grid Cell Level for Large Scale Hydrologic Models : A Review ». Agromet 35, n^o 2 (12 août 2021) : 60–72. http://dx.doi.org/10.29244/j.agromet.35.2.60-72.

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New tools and concepts in the form of mathematical models, remote sensing and Geographic Information System (GIS), communication and telemetering have been developed for the complex hydrologic systems that permit a different analysis of processes and allow watershed to be considered as an integrated planning and management unit. Hydrological characteristics can be generated through spatial analysis, and ready for input into a distributed hydrologic models to define adequately the hydrological response of a watershed that can be related back to the specific environmental, climatic, and geomorphic conditions. In the present paper, some recent development in hydrologic modeling will be reviewed with recognition of the role of horizontal routing scheme in large scale hydrologic modeling. Among others, these developments indicated the needs of alternative horizontal routing models at grid scale level that can be coupled to land surface parameterization schemes that presently still employed the linear routing model. Non-linear routing scheme will be presented and discussed in this paper as possible extension.

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Sharma, Ashish, Suresh Hettiarachchi et Conrad Wasko. « Estimating design hydrologic extremes in a warming climate : alternatives, uncertainties and the way forward ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 379, n^o 2195 (mars 2021) : 20190623. http://dx.doi.org/10.1098/rsta.2019.0623.

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It is now well established that our warming planet is experiencing changes in extreme storms and floods, resulting in a need to better specify hydrologic design guidelines that can be projected into the future. This paper attempts to summarize the nature of changes occurring and the impact they are having on the design flood magnitude, with a focus on the urban catchments that we will increasingly reside in as time goes on. Two lines of reasoning are used to assess and model changes in design hydrology. The first of these involves using observed storms and soil moisture conditions and projecting how these may change into the future. The second involves using climate model simulations of the future and using them as inputs into hydrologic models to assess the changed design estimates. We discuss here the limitations in both and suggest that the two are, in fact, linked, as climate model projections for the future are needed in the first approach to form meaningful projections for the future. Based on the author's experience with both lines of reasoning, this invited commentary presents a theoretical narrative linking these two and identifying factors and assumptions that need to be validated before implementation in practice. This article is part of a discussion meeting issue ‘Intensification of short-duration rainfall extremes and implications for flash flood risks’.

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Shindell, Drew. « Estimating the potential for twenty-first century sudden climate change ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 365, n^o 1860 (30 juillet 2007) : 2675–94. http://dx.doi.org/10.1098/rsta.2007.2088.

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I investigate the potential for sudden climate change during the current century. This investigation takes into account evidence from the Earth's history, from climate models and our understanding of the physical processes governing climate shifts. Sudden alterations to climate forcing seem to be improbable, with sudden changes instead most likely to arise from climate feedbacks. Based on projections from models validated against historical events, dramatic changes in ocean circulation appear unlikely. Ecosystem–climate feedbacks clearly have the potential to induce sudden change, but are relatively poorly understood at present. More probable sudden changes are large increases in the frequency of summer heatwaves and changes resulting from feedbacks involving hydrology. These include ice sheet decay, which may be set in motion this century. The most devastating consequences are likely to occur further in the future, however. Reductions in subtropical precipitation are likely to be the most severe hydrologic effects this century, with rapid changes due to the feedbacks of relatively well-understood large-scale circulation patterns. Water stress may become particularly acute in the Southwest US and Mexico, and in the Mediterranean and Middle East, where rainfall decreases of 10–25% (regionally) and up to 40% (locally) are projected.

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Reichert, P., G. White, M. J. Bayarri et E. B. Pitman. « Mechanism-based emulation of dynamic simulation models : Concept and application in hydrology ». Computational Statistics & ; Data Analysis 55, n^o 4 (avril 2011) : 1638–55. http://dx.doi.org/10.1016/j.csda.2010.10.011.

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