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Exposure Assessment Models

Model Performance Evaluation and Scenario Analysis (MPESA)

Introduction

The Model Performance Evaluation and Scenario Analysis (MPESA) Tool was developed to provide users with the ability to assess the performance with which models predict time series data (e.g., streamflow). The tool was developed specifically for the Hydrological Simulation Program-Fortran (HSPF) and the Stormwater Management Model (SWMM) models.


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Audience

The MPSA was developed primarily for hydrological and water quality modelers.


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Abstract

As the name implies, the tool consists of Model Performance Evaluation and Baseline and Scenario Analysis (MPESA) components. The Model Performance Evaluation and Diagnostics component calculates model performance evaluation measures such as descriptive statistics, error analysis, weighted ranks, serial and cross-correlation analysis, and Nash-Sutcliffe model efficiency. The model performance evaluation is based on the time series separation and reconstruction (TSSR) paradigm whereby a time series data is separated into magnitude or duration curve and sequence components. It demonstrates if model performance is impacted by magnitude or sequence related errors and provides limited diagnostic feedback to modelers on model calibration. The program has zooming and visualization capabilities. The Baseline and Scenario Comparison component of the tool provide the user with quantitative evaluation of baseline and scenario comparisons. This component uses metrics such as low flow analyses, metrics of flashiness, flow magnitudes, as well as flow threshold analyses. The scenario analysis tool is useful for land use and climate change baseline and scenario comparisons.


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Applications and Possible Uses

The most common use of the web-based MPESA Tool is evaluating model performance through comparisons of observed and predicted time series data. The tool receives observed and predicted or baseline and scenario data and calculates model performance metric, baseline and scenario indices, and visualization and zooming capabilities.


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Software History

Based on future test results and user requests, MPESA may undergo additional enhancements.


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Technical Support and Training

Questions regarding MPESA can be directed to ceam@epa.gov at the EPA’s National Exposure Research Laboratory in Athens, GA.  A tutorial is now available for download at MPESA Download.


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Notice

This tutorial has been reviewed by the National Exposure Research Laboratory (NERL), U.S. Environmental Protection Agency (USEPA), Athens, Georgia and approved for publication. The author and the U.S. Environmental Protection Agency are not responsible and assume no liability whatsoever for any results or any use made of the results obtained from this program, nor for any damages or litigation that result from the use of this tool for any purpose.


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