Recommendations for Developing Useful and Usable Convection-Allowing Model Ensemble Information for NWS Forecasters

2020 ◽  
Vol 35 (4) ◽  
pp. 1381-1406 ◽  
Author(s):  
Julie L. Demuth ◽  
Rebecca E. Morss ◽  
Isidora Jankov ◽  
Trevor I. Alcott ◽  
Curtis R. Alexander ◽  
...  
Keyword(s):  
Research Effort ◽  
Model Development ◽  
Weather Forecast ◽  
Model Verification ◽  
Subjective Assessments ◽  
Operational Forecasting ◽  
Semistructured Interviews ◽  
Objective Model ◽  
Weather Risks ◽  
Hazardous Weather

AbstractU.S. National Weather Service (NWS) forecasters assess and communicate hazardous weather risks, including the likelihood of a threat and its impacts. Convection-allowing model (CAM) ensembles offer potential to aid forecasting by depicting atmospheric outcomes, including associated uncertainties, at the refined space and time scales at which hazardous weather often occurs. Little is known, however, about what CAM ensemble information is needed to inform forecasting decisions. To address this knowledge gap, participant observations and semistructured interviews were conducted with NWS forecasters from national centers and local weather forecast offices. Data were collected about forecasters’ roles and their forecasting processes, uses of model guidance and verification information, interpretations of prototype CAM ensemble products, and needs for information from CAM ensembles. Results revealed forecasters’ needs for specific types of CAM ensemble guidance, including a product that combines deterministic and probabilistic output from the ensemble as well as a product that provides map-based guidance about timing of hazardous weather threats. Forecasters also expressed a general need for guidance to help them provide impact-based decision support services. Finally, forecasters conveyed needs for objective model verification information to augment their subjective assessments and for training about using CAM ensemble guidance for operational forecasting. The research was conducted as part of an interdisciplinary research effort that integrated elicitation of forecasters’ CAM ensemble needs with model development efforts, with the aim of illustrating a robust approach for creating information for forecasters that is truly useful and usable.

A systematic approach for model verification: application on seven published activated sludge models

2010 ◽  
Vol 61 (4) ◽  
pp. 825-839 ◽  
Author(s):  
H. Hauduc ◽  
L. Rieger ◽  
I. Takács ◽  
A. Héduit ◽  
P. A. Vanrolleghem ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Systematic Approach ◽  
Model Development ◽  
Model Verification ◽  
Software Implementation ◽  
Model Description ◽  
Kinetic Rate ◽  
Simulation Results ◽  
Activated Sludge Models

The quality of simulation results can be significantly affected by errors in the published model (typing, inconsistencies, gaps or conceptual errors) and/or in the underlying numerical model description. Seven of the most commonly used activated sludge models have been investigated to point out the typing errors, inconsistencies and gaps in the model publications: ASM1; ASM2d; ASM3; ASM3 + Bio-P; ASM2d + TUD; New General; UCTPHO+. A systematic approach to verify models by tracking typing errors and inconsistencies in model development and software implementation is proposed. Then, stoichiometry and kinetic rate expressions are checked for each model and the errors found are reported in detail. An attached spreadsheet (see http://www.iwaponline.com/wst/06104/0898.pdf) provides corrected matrices with the calculations of all stoichiometric coefficients for the discussed biokinetic models and gives an example of proper continuity checks.

Exposing System and Model Disparity and Agreement Using Wavelets

2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Andrew D. Atkinson ◽  
Raymond R. Hill ◽  
Joseph J. Pignatiello ◽  
G. Geoffrey Vining ◽  
Edward D. White ◽  
...  
Keyword(s):  
Development Process ◽  
Model Development ◽  
Model Verification ◽  
Verification And Validation ◽  
High Dimensional ◽  
Model Data ◽  
Accurate Representation ◽  
Model Verification And Validation ◽  
Model Development Process ◽  
Functional Output

Model verification and validation (V&V) remain a critical step in the simulation model development process. A model requires verification to ensure that it has been correctly transitioned from a conceptual form to a computerized form. A model also requires validation to substantiate the accurate representation of the system it is meant to simulate. Validation assessments are complex when the system and model both generate high-dimensional functional output. To handle this complexity, this paper reviews several wavelet-based approaches for assessing models of this type and introduces a new concept for highlighting the areas of contrast and congruity between system and model data. This concept identifies individual wavelet coefficients that correspond to the areas of discrepancy between the system and model.

Development of Rail Temperature Predictions to Minimize Risk of Track Buckle Derailments

2013 ◽  
Author(s):  
Radim Bruzek ◽  
Larry Biess ◽  
Leith Al-Nazer
Keyword(s):  
Weather Forecast ◽  
Model Verification ◽  
Order Process ◽  
Railroad Track ◽  
Significant Cost ◽  
Web Based ◽  
Increased Risk ◽  
Forecast Data ◽  
Verification Process ◽  
Web Based System

Track buckling due to excessive rail temperature is a major cause of derailments with serious consequences. To minimize the risk of derailments, slow orders are typically issued on sections of track in areas where an elevated rail temperature is expected and risk of track buckling is increased. While the slow orders are an important preventive safety measure, they are costly as they disrupt timetables and can affect time-sensitive shipments. Optimizing the slow order process would result in significant cost saving for the railroads. The Federal Railroad Administration’s (FRA’s) Office of Research and Development has sponsored the development of a model for predicting rail temperatures using real time weather forecast data and predefined track parameters and a web-based system for providing resulting information to operators. In cooperation with CSX Transportation (CSX), ENSCO Inc. conducted a model verification study by comparing actual rail temperatures measured by wayside sensors installed on railroad track near Folkston, GA, with the rail temperatures predicted by the model based on weather forecast data over the course of summer 2011. The paper outlines the procedure of the verification process together with correlation results, which are favorable. The paper also presents results of several case studies conducted on derailments attributed to track buckling. These investigations improve our understanding of conditions and temperature patterns leading to increased risk of rail buckles and validate further use of the Rail Temperature Prediction Model as track buckling prediction tool and as an aid to the railroads in making more informed decisions on slow order issuing process.

scholarly journals Salud, género y clima en migrantes internos e internacionales por Sonora, México

2019 ◽  
Vol 8 (2) ◽  
pp. 171
Author(s):  
José Eduardo Calvario Parra ◽  
Rolando Enríque Díaz Caravantes
Keyword(s):  
High Temperatures ◽  
United States Of America ◽  
Qualitative Method ◽  
Turning Point ◽  
The United States ◽  
The People ◽  
Northern Border ◽  
Semistructured Interviews ◽  
Internal Migrants ◽  
Weather Risks

Introducción: La experiencia migratoria tanto interna como internacional está compuesta por un conjunto de situaciones de peligros y riesgos que ponen en jaque la integridad física y emocional de las personas. El objetivo de este artículo es documentar las experiencias de los/as migrantes ante altas temperaturas y su salud tanto de quienes se dirigen de México o Centroamérica hacia los Estados Unidos de América como los que se desplazan al interior de México rumbo a los campos agrícolas del noroeste.Método: Este trabajo se basa en un estudio de corte cualitativo por medio de entrevistas semiestructuradas sobre el riesgo climático y la salud en migrantes internacionales e internos en la frontera norte de México, particularmente en el estado de Sonora.Resultados: La migración es un punto de inflexión en la vida de las personas entrevistadas. Existe una asocación cualitativa entre la masculinidad y el hecho de emigrar; la noción de proveduria e idea de la aventura son cruciales para entender el proceso migratorio. El afrontar distintos peligros como la violencia y los factores medioambientales generan daños físicos y emocionales.Discusión y/o Conclusión: Existe un proceso de relativización del riesgo climático, en este caso, la minimización de los daños en la salud por las altas temperaturas. La idea de la autosuficiencia e independencia es parte de las identidades de género en los varones migrantes entrevistados. Introduction: The migrational experience, both internal and international is composed by a combination of hazardous and risk situations that threaten the physical and emotional integrity of individuals. The goal of this article is to document the experiences and the health of migrants facing high temperatures when heading from Mexico or Central America towards the United States of America, as well as those that transit through the interior of Mexico towards the agricultural fields of the Northwest.Method: These findings are based on a qualitative method study that used semistructured interviews that delve into weather and health risks in international and internal migrants on the Mexican northern border, particularly in the state of Sonora.Results: Migration is a turning point in the lives of the people interviewed. There exists a qualitative association between masculinity and the act of migrating; the notion of being a provider and the idea of adventure are crucial for understanding the migrational process. Facing different hazards like violence and environmental factors generates physical and emotional damage.Conclusion: There exists a relativization process of weather risks, on this case, the minimization of the damage to health due to high temperatures. The idea of selfsufficiency and independence is part of the gender identities of the migrant males interviewed.

scholarly journals Synthesis of a CFD Benchmark Exercise: Examining Fluid Flow and Residence-Time Distribution in a Water Model of Tundish

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5453
Author(s):  
Dong-Yuan Sheng
Keyword(s):  
Best Practice ◽  
Model Development ◽  
Practical Interest ◽  
Turbulence Models ◽  
Fluid Simulation ◽  
Model Verification ◽  
Water Model ◽  
Cfd Simulations ◽  
Cfd Models ◽  
Selection Of

Computational Fluid Dynamics (CFD) has become an indispensable tool that can potentially predict many phenomena of practical interest in the tundish. Model verification and validation (V&V) are essential parts of a CFD model development process if the models are to be used with sufficient confidence in real industrial tundish applications. The crucial aspects of CFD simulations in the tundish are addressed in this study, such as the selection of the turbulence models, meshing, boundary conditions, and selection of discretization schemes. A series of CFD benchmarking exercises are presented serving as selected examples of appropriate modelling strategies. A tundish database, initiated by German Steel Institute VDEH working group “Fluid Mechanics and Fluid Simulation”, was revisited with the aim of establishing a comprehensive set of best practice guidelines (BPG) in CFD simulations for tundish applications. These CFD benchmark exercises yield important results for the sensible application of CFD models and contribute to further improving the reliability of CFD applications in metallurgical reactors.

scholarly journals Code-to-code verification of an axisymmetric model of the Bridgman solidification process for alloys

2017 ◽  
Vol 27 (5) ◽  
pp. 1142-1157 ◽  
Author(s):  
Mirosław Seredyński ◽  
Sara Battaglioli ◽  
Robin P. Mooney ◽  
Anthony J. Robinson ◽  
Jerzy Banaszek ◽  
...  
Keyword(s):  
Numerical Models ◽  
Model Development ◽  
Solidification Process ◽  
Model Verification ◽  
Code Verification ◽  
Ansys Fluent ◽  
Content Type ◽  
Rate Step ◽  
Radial Heat ◽  
Bridgman Solidification

Purpose Numerical models of manufacturing processes are useful and provide insight for the practitioner; however, model verification and validation are a prerequisite for expedient application. This paper aims to detail the code-to-code verification of a thermal numerical model for the Bridgman solidification process of alloys in a two-dimensional axisymmetric domain, against an established commercial code (ANSYS Fluent); the work is considered a confidence building step in model development. Design/methodology/approach A grid sensitivity analysis is carried out to establish grid independence, and this is followed by simulations of two transient solidification scenarios: pulling rate step change and ramp input; the results of which are compared and discussed. Findings Good conformity of results is achieved; hence, the non-commercial model is code-to-code verified; in addition, the ability of the non-commercial model to deal with radial heat flow is demonstrated. Originality/value The ability of the home made model for Bridgman furnace solidification to deal with cases where significant radial heat transfer occurs in the sample was demonstrated. The introduction of front tracking to model the macroscopic growth of dendritic mush and the region of undercooled liquid is identified as the next step in model development.

scholarly journals eWaterCycle: a hyper-resolution global hydrological model for river discharge forecasts made from open source pre-existing components

2016 ◽  
Author(s):  
Rolf Hut ◽  
Niels Drost ◽  
Maarten van Meersbergen ◽  
Edwin Sutanudjaja ◽  
Marc Bierkens ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Data Assimilation ◽  
Open Source ◽  
River Discharge ◽  
Model Comparison ◽  
Weather Forecast ◽  
Model Ensemble ◽  
Basic Model ◽  
Operational Forecasting ◽  
The Impact

Abstract. eWaterCycle is an open source hyperresolution (10 km × 10 km) global hydrological forecasting framework that runs an ensemble of hydrological models. Forced with a weather forecast ensemble, it predicts river discharge and river discharge uncertainty nine days ahead. Daily satellite soil moisture observations are assimilated into the state of the model ensemble using an Ensemble Kalman Filter. We demonstrate that it is feasible to build such a system using pre-exisiting, open source, components that communicate through standard interfaces. The PCRGLOBWB2.0 (van Beek et al., 2011; Sutanudjaja et al., 2014) model is used to model hydrology globally, forced with GFS (Kanamitsu, 1989; Kanamitsu et al., 1991; Moorthi et al., 2001) weather forecast. The operational soil moisture product from the HSAF (Drusch et al., 2009; De Rosnay et al., 2011) service is assimilated into the model ensemble using OpenDA (Velzen et al., 2016), a data assimilation framework. Output of the model ensemble is presented in a Cesium (Analytical Graphics, 2011) based visualization. All communication between framework components is through standard file types (NetCDF)(Rew and Davis, 1990) and services (Web Map Service) (de La Beaujardiere, 2006). Communication between model and data assimilation framework is through the Basic Model Interface (BMI) (Peckham et al., 2013). The forecasts is available at forecast.ewatercycle.org. By using standard open interfaces, the different components of the model can be replaced with relative ease, facilitating future model comparison studies without the need of extensive Computer Science support. This makes eWaterCycle, in addition to an operational forecasting model, a testbed environment where the impact of different model structures, input sources and/or data assimilation schemes can easily be studied. Setup instructions to run the eWaterCycle project on local hardware are provided, allowing the hydrological community to build on this open source framework.

Occupant Modeling for Injury Risk Computation in Vehicle Fleet Frontal Crash Simulations

2013 ◽  
Author(s):  
Randa Radwan Samaha ◽  
Priyaranjan Prasad ◽  
Sarath Kamalakkannan ◽  
Vamsi Kommineni ◽  
Lilly Nix ◽  
...  
Keyword(s):  
Test Data ◽  
Injury Risk ◽  
Seat Belt ◽  
Model Development ◽  
Model Verification ◽  
Small Female ◽  
Passenger Car ◽  
Frontal Crash ◽  
Vehicle Data ◽  
Scale Test

Occupant model environments (MADYMO) are developed for four surrogate vehicles for injury risk computation in frontal crash fleet simulations: a small passenger car, a midsize passenger car, a midsize sport utility vehicle and a full size pickup truck. This research supports the initial implementation of a novel methodology for Evaluating Fleet, i.e., self and partner, Protection (EFP) of new vehicle designs through a systems modeling approach driven by structural and occupant modeling and real world crash and full scale test data. A two part general framework for development of occupant models for fleet vehicles is established: model development (Part I) and model verification and robustness evaluation (Part II). In Part I, current generic occupant models with seat belt and airbag restraints are obtained from restraint manufacturers and then modified to reflect the interior geometry and clearances of the desired vehicle. Data from finite element structural simulations, including the occupant compartment geometry, crash pulse, and toe pan intrusions, are utilized to drive the MADYMO models. Restraint system and dummy seating changes are incorporated to achieve a realistic match for both midsize male and small female driver dummy responses from available frontal crash tests. Part II involves comparing occupant responses from simulation and test data, and assessing trends in occupant responses in selected crash configurations for application in frontal crash fleet simulations.

scholarly journals Simulation of the Heat Transfer in a Gas Turbine Combustor Fueled With Coal-Water Mixture: Part 1 — Model Development and Verification

1986 ◽  
Author(s):  
Ihab H. Farag ◽  
Joseph Vaillancourt
Keyword(s):  
Heat Transfer ◽  
Water Content ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Model Development ◽  
Significant Loss ◽  
Model Verification ◽  
Water Mixture ◽  
Gas Turbine Combustor ◽  
Coal Particles

It is possible to disperse high concentrations of finely pulverized beneficiated coal in water to produce a stable coal-water slurry fuel (CWF). One of the potential applications of CWF is as a fuel in gas turbines. This represents a relatively novel, developing technology. Coal beneficiation to the level needed for gas turbine application (< 1 percent ash) requires fine grinding of the coal particles to less than 15 μm necessitating increase in water content of the slurry to avoid increased CWS viscosity due to the finer particles. The gas turbine cycle is capable of accommodating an increased water content of the fuel without a significant loss in efficiency. The objective of the present study is to develop and verify a computer model to simulate the heat transfer processes taking place in a gas turbine combustor (GTC) burning a CWF. The model predicts the species and the temperature distribution throughout the GTC, the heat flux patterns and the contribution of both convection and radiation to the total heat transfer rate. Model verification includes cases of cold flow without combustion, combustion without heat release, combustion without convection and/or radiation, verification of exchange areas and an overall energy balance check.

scholarly journals The General Principles of the Transportation Simulation Model Development and Validation

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Simulation Model ◽  
Model Validation ◽  
Management Strategies ◽  
Model Development ◽  
Simulation Models ◽  
Model Verification ◽  
Microscopic Simulation ◽  
Calibration Methods ◽  
Transportation Simulation ◽  
Development And Validation

Transportation simulation model development allows simulating traveller’s decisions, evaluating various transportation management strategies and complex solutions. The aim of the paper is to set the general principles of the transportation simulation model development and validation. The paper contains the overview of the transportation simulation models types with the examples from the conducted projects for the Riga city. The basic steps of the simulation model development procedure: initial data preparation and analysis, transportation model development and simulation, scenarios planning and evaluation, and simulation models outcomes evaluation are considered. Simulation model verification, validation and calibration definitions are given. The basic checks for the transportation macroscopic and microscopic simulation model validation are listed. A summary of the transportation simulation model validation and calibration methods and parameters is given.

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