Simulating dune evolution on managed coastlines: Exploring management options with the Coastal Recovery from Storms Tool (CReST)

Shore & Beach ◽  
2019 ◽  
pp. 36-43
Author(s):  
Peter Ruggiero ◽  
Nicholas Cohn ◽  
Bas Hoonhout ◽  
Evan Goldstein ◽  
Sierd de Vries ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Time Scales ◽  
Complex Dynamics ◽  
Coastal Dunes ◽  
Anthropogenic Pressures ◽  
Model Framework ◽  
Management Options ◽  
Engineering Structures ◽  
Modeling Tools ◽  
Dune Grass

Despite the importance of coastal dunes to many low-lying coastal communities and ecosystems, our understanding of how both climatic and anthropogenic pressures affect foredune evolution on time scales of years to decades is relatively poor. However, recently developed coupled numerical modeling tools have allowed for the exploration of the erosion and growth of coastal foredunes on time scales of hours to years. For example, Windsurf is a new process-based numerical modeling system (Cohn et al. 2019a) that simulates the evolution of dune-backed sandy coastal systems in response to wave, wind, and water level forcings. CReST, developed as a front-end interface to Windsurf, aims to add the ability to incorporate beach nourishment and dune construction, beach and dune grading, dune grass planting scenarios, dune grass removal, and the presence of hard engineering structures into the model framework to better account for the complex dynamics of managed coastlines. Initial model sensitivity tests suggest that the model provides a flexible framework to investigate the complex interactions between beaches and dunes for a variety of exploratory and applied applications.

scholarly journals Simulation of leaf curl disease dynamics in chili for strategic management options

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Buddhadeb Roy ◽  
Shailja Dubey ◽  
Amalendu Ghosh ◽  
Shalu Misra Shukla ◽  
Bikash Mandal ◽  
...  
Keyword(s):  
Disease Risk ◽  
Virus Transmission ◽  
Host Population ◽  
High Rate ◽  
Disease Dynamics ◽  
Model Framework ◽  
Management Options ◽  
Transmission Parameters ◽  
Vector Population ◽  
Leaf Curl

AbstractLeaf curl, a whitefly-borne begomovirus disease, is the cause of frequent epidemic in chili. In the present study, transmission parameters involved in tripartite interaction are estimated to simulate disease dynamics in a population dynamics model framework. Epidemic is characterized by a rapid conversion rate of healthy host population into infectious type. Infection rate as basic reproduction number, R0 = 13.54, has indicated a high rate of virus transmission. Equilibrium population of infectious host and viruliferous vector are observed to be sensitive to the immigration parameter. A small increase in immigration rate of viruliferous vector increased the population of both infectious host and viruliferous vector. Migrant viruliferous vectors, acquisition, and transmission rates as major parameters in the model indicate leaf curl epidemic is predominantly a vector -mediated process. Based on underlying principles of temperature influence on vector population abundance and transmission parameters, spatio-temporal pattern of disease risk predicted is noted to correspond with leaf curl distribution pattern in India. Temperature in the range of 15–35 °C plays an important role in epidemic as both vector population and virus transmission are influenced by temperature. Assessment of leaf curl dynamics would be a useful guide to crop planning and evolution of efficient management strategies.

Complex dynamics of fault zone deformation under large dam at various time scales

2019 ◽  
Vol 5 (4) ◽  
pp. 437-455
Author(s):  
Tamaz Chelidze ◽  
Teimuraz Matcharashvili ◽  
Vakhtang Abashidze ◽  
Temur Tsaguria ◽  
Nadezhda Dovgal ◽  
...  
Keyword(s):  
Fault Zone ◽  
Time Scales ◽  
Complex Dynamics ◽  
Large Dam ◽  
Zone Deformation

scholarly journals A Novel Approach to the Design and Analysis of Field Experiments to Study Variation in the Tolerance and Resistance of Cultivars to Root Lesion Nematodes (Pratylenchus spp.)

2020 ◽  
Vol 110 (10) ◽  
pp. 1623-1631
Author(s):  
Karyn L. Reeves ◽  
Clayton R. Forknall ◽  
Alison M. Kelly ◽  
Kirsty J. Owen ◽  
Joshua Fanning ◽  
...  
Keyword(s):  
Mixed Model ◽  
Field Experiments ◽  
Linear Mixed Model ◽  
Random Regression ◽  
Yield Response ◽  
Response Curves ◽  
Model Framework ◽  
Management Options ◽  
Nematode Reproduction ◽  
Yield Response Curves

The root lesion nematode (RLN) species Pratylenchus thornei and P. neglectus are widely distributed within cropping regions of Australia and have been shown to limit grain production. Field experiments conducted to compare the performance of cultivars in the presence of RLNs investigate management options for growers by identifying cultivars with resistance, by limiting nematode reproduction, and tolerance, by yielding well in the presence of nematodes. A novel experimental design approach for RLN experiments is proposed where the observed RLN density, measured prior to sowing, is used to condition the randomization of cultivars to field plots. This approach ensured that all cultivars were exposed to consistent ranges of RLN in order to derive valid assessments of relative cultivar tolerance and resistance. Using data from a field experiment designed using the conditioned randomization approach and conducted in Formartin, Australia, the analysis of tolerance and resistance was undertaken in a linear mixed model framework. Yield response curves were derived using a random regression approach and curves modeling change in RLN densities between sowing and harvest were derived using splines to account for nonlinearity. Groups of cultivars sharing similar resistance levels could be identified. A comparison of slopes of yield response curves of cultivars belonging to the same resistance class identified differing tolerance levels for cultivars with equivalent exposures to both presowing and postharvest RLN densities. As such, the proposed design and analysis approach allowed tolerance to be assessed independently of resistance.

Finite-difference modeling of wave propagation and diffusion in poroelastic media

Geophysics ◽  
2009 ◽  
Vol 74 (4) ◽  
pp. T55-T66 ◽  
Author(s):  
Fabian Wenzlau ◽  
Tobias M. Müller
Keyword(s):  
Numerical Modeling ◽  
Finite Difference ◽  
Diffusion Processes ◽  
Spatial Scales ◽  
Rock Physics ◽  
Seismic Attenuation ◽  
Rock Properties ◽  
Modeling Tools ◽  
Reservoir Rocks ◽  
Poroelastic Media

Numerical modeling of seismic waves in heterogeneous, porous reservoir rocks is an important tool for interpreting seismic surveys in reservoir engineering. Various theoretical studies derive effective elastic moduli and seismic attributes from complex rock properties, involving patchy saturation and fractured media. To confirm and further develop rock-physics theories for reservoir rocks, accurate numerical modeling tools are required. Our 2D velocity-stress, finite-difference scheme simulates waves within poroelastic media as described by Biot’s theory. The scheme is second order in time, contains high-order spatial derivative operators, and is parallelized using the domain-decomposition technique. A series of numerical experiments that are compared to exact analytical solutions allow us to assess the stability conditions and dispersion relations of the explicit poroelastic finite-differ-ence method. The focus of the experiments is to model wave-induced flow accurately in the vicinity of mesoscopic heterogeneities such as cracks and gas inclusions in partially saturated rocks. For that purpose, a suitable numerical setup is applied to extract seismic attenuation and dispersion from quasi-static experiments. Our results confirm that finite-difference modeling is a valuable tool to simulate wave propa-gation in heterogeneous poroelastic media, provided the temporal and spatial scales of the propagating waves and of the induced fluid-diffusion processes are resolved properly.

Numerical modeling of multiple length scales in thermal transport processes

2014 ◽  
Vol 24 (4) ◽  
pp. 781-796 ◽  
Author(s):  
Yogesh Jaluria
Keyword(s):  
Numerical Modeling ◽  
Boundary Conditions ◽  
Time Scales ◽  
Transport Processes ◽  
Thermal Processes ◽  
Length Scales ◽  
Content Type ◽  
Multiple Length Scales ◽  
Wide Range ◽  
Simulation Results

Purpose – Multiple length and time scales arise in a wide variety of practical and fundamental problems. It is important to obtain accurate and validated numerical simulation results, considering the different scales that exist, in order to predict, design and optimize the behavior of practical thermal processes and systems. The purpose of this paper is to present modeling at the different length scales and then addresses the question of coupling the different models to obtain the overall model for the system or process. Design/methodology/approach – Both numerical and experimental methods to obtain results at the different length scales, particularly at micro and nanoscales, are considered. Even though the paper focusses on length scales, multiple time scales lead to similar concerns and are also considered. The two circumstances considered in detail are multiple length scales in different domains and those in the same domain. These two cases have to be modeled quite differently in order to obtain a model for the overall process or system. The basic considerations involved in such a modeling are discussed. A wide range of thermal processes are considered and the methods that may be used are presented. The models employed must be validated and the accuracy of the simulation results established if the simulation results are to be used for prediction, control and design. Findings – Of particular interest are concerns like verification and validation, imposition of appropriate boundary conditions, and modeling of complex, multimode transport phenomena in multiple scales. Additional effects such as viscous dissipation, surface tension, buoyancy and rarefaction that could arise and complicate the modeling are discussed. Uncertainties that arise in material properties and in boundary conditions are also important in design and optimization. Large variations in the geometry and coupled multiple regions are also discussed. Research limitations/implications – The paper is largely focussed on multiple-scale considerations in thermal processes. Both numerical modeling/simulation and experimentation are considered, with the latter being used for validation and physical insight. Practical implications – Several examples from materials processing, environmental flows and electronic systems, including data centers, are given to present the different techniques that may be used to achieve the desired level of accuracy and predictability. Originality/value – Present state of the art and future needs in this interesting and challenging area are discussed, providing the impetus for further work. Different methods for treating multiscale problems are presented.

Experimental and Numerical Modeling Tools for Conventional Hydropower Systems

2016 ◽  
pp. 448-464 ◽  
Author(s):  
Zhiqun Daniel Deng ◽  
Thomas J. Carlson ◽  
Gene R. Ploskey ◽  
Richard S. Brown ◽  
Gary E. Johnson ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Modeling Tools ◽  
Experimental And Numerical Modeling

scholarly journals Testing a river basin model with sensitivity analysis and autocalibration for an agricultural catchment in SW Finland

2009 ◽  
Vol 18 (3-4) ◽  
pp. 428-439 ◽  
Author(s):  
S. TATTARI ◽  
J. KOSKIAHO ◽  
I. BÄRLUND
Keyword(s):  
Sensitivity Analysis ◽  
River Basin ◽  
Swat Model ◽  
Protective Measure ◽  
Background Information ◽  
Cultivated Plants ◽  
Nutrient Loads ◽  
Management Options ◽  
Modeling Tools ◽  
Management Actions

Modeling tools are needed to assess (i) the amounts of loading from agricultural sources to water bodies as well as (ii) the alternative management options in varying climatic conditions. These days, the implementation of Water Framework Directive (WFD) has put totally new requirements also for modeling approaches. The physically based models are commonly not operational and thus the usability of these models is restricted for a few selected catchments. But the rewarding feature of these process-based models is an option to study the effect of protection measures on a catchment scale and, up to a certain point, a possibility to upscale the results. In this study, the parameterization of the SWAT model was developed in terms of discharge dynamics and nutrient loads, and a sensitivity analysis regarding discharge and sediment concentration was made. The SWAT modeling exercise was carried out for a 2nd order catchment (Yläneenjoki, 233 km2) of the Eurajoki river basin in southwestern Finland. The Yläneenjoki catchment has been intensively monitored during the last 14 years. Hence, there was enough background information available for both parameter setup and calibration. In addition to load estimates, SWAT also offers possibility to assess the effects of various agricultural management actions like fertilization, tillage practices, choice of cultivated plants, buffer strips, sedimentation ponds and constructed wetlands (CWs) on loading. Moreover, information on local agricultural practices and the implemented and planned protective measures were readily available thanks to aware farmers and active authorities. Here, we studied how CWs can reduce the nutrient load at the outlet of the Yläneenjoki river basin. The results suggested that sensitivity analysis and autocalibration tools incorporated in the model are useful by pointing out the most influential parameters, and that flow dynamics and annual loading values can be modeled with reasonable accuracy with SWAT. Sensitivity analysis thus showed the parameters which should be known better in order to result in more realistic parameter values. Moreover, the scenario runs for CWs made with SWAT revealed the high demand of land area for this protective measure to be substantially effective.;

Evaluation of environmental heterogeneity and its effect on arbuscular mycorrhizal interaction in coastal dunes

2021 ◽  
Vol 51 ◽  
pp. e1371
Author(s):  
Uriel Ramón Jakuosi Solís-Rodríguez ◽  
Patricia Guadarrama ◽  
Laura Hernández-Cuevas ◽  
Luis Salinas-Peba ◽  
José Ramos-Zapata
Keyword(s):  
Mycorrhizal Fungi ◽  
Environmental Heterogeneity ◽  
Biosphere Reserve ◽  
Arbuscular Mycorrhizal ◽  
Coastal Dunes ◽  
Common Species ◽  
Anthropogenic Pressures ◽  
The Status ◽  
Salt Industry

Background: Coastal dune scrub vegetation is established on a substrate that favors biodiversity, but this is currently restricted to small patches. Objective: To determine the status of the arbuscular mycorrhizal fungi (AMF) in this vegetation under different anthropogenic pressures and to propose actions addressing its conservation and restoration. Methods: Plant and fungal community was characterized through taxonomic identification of the AMF and determination of their percentage of viability, number of infective propagules (NIP) and percentage of mycorrhizal colonization. Three contrasting sites were identified in the Ría Lagartos Biosphere Reserve: C = Conserved, IPS = Intermediate perturbation by the salt industry and HPA = high perturbation of anthropogenic origin. In each site, fine roots were collected from 12 common species and compound soil samples were taken. Results and conclusions: Eight AMF species were identified, in IPS, the highest values were presented in terms of percentage of colonization 55.43 ± 6.5, NIP = 142.07 ± 91.2 and viability = 27.6 ± 15.21 % while, in HPA, a higher number of healthy spores were found 43.6 ± 11.5/50 g. Infective propagules are an indicator of a “healthy ecosystem” and were found at a higher proportion in the conserved site.

NUMERICAL MODELING OF THE IMPACT OF QUARANTINE MEASURES ON THE DYNAMICS OF THE EPIDEMIOLOGICAL PROCESS BASED ON THE SEIRD MODEL

2021 ◽  
Vol 7 (2) ◽  
pp. 170-187
Author(s):  
Nina I. Eremeeva
Keyword(s):  
Mathematical Modeling ◽  
Numerical Modeling ◽  
Dynamic Models ◽  
Numerical Calculations ◽  
Short Term ◽  
Modeling Tools ◽  
Population Immunity ◽  
Restrictive Measures ◽  
The Impact

The COVID-19 epidemic has once again demonstrated the importance of predicting the development of various processes and calculating the consequences. “How effective is the introduction of strict quarantine measures?” and “Will the quarantine be able to stop the epide­mic?” — these questions still have no clear answer. This article aims to answer these questions using mathematical modeling tools using the SEIRD model, modified to account for the peculiarities of the spread of COVID-19. The SEIRD model belongs to the class of differential dynamic models, which allows quick experimentation to predict the spread of the disease and calculate its influence on the development of certain processes. Based on numerical modeling, the author demonstrates that insufficient quarantine measures provide only a temporary effect. After they end, with an insufficient level of “population immunity”, the epidemic starts growing again, leading to a second morbidity peak. This paper presents numerical calculations to track the duration impact and quarantine measures’ severity on the dynamics of the epidemiological process. The results show that strict restrictive measures are not always effective, and strict short-term measures have less effect than softer, but long-term measures. In addition, the author provides an example of finding the parameters of quarantine measures that ensure fixed limits on the morbidity level during the epidemic.

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