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Ensemble Models
Citation:
FUENTES, M. AND K. FOLEY. Ensemble Models. 2nd, Chapter E, Abdel H. El-Shaarawi, Walter W. Piegorsch (ed.), Encyclopedia of Environmetrics. John Wiley & Sons, Ltd., Indianapolis, IN, , 851-853, (2012).
Impact/Purpose:
The National Exposure Research Laboratory′s (NERL′s) Atmospheric Modeling and Analysis Division (AMAD) conducts research in support of EPA′s mission to protect human health and the environment. AMAD′s research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the Nation′s air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for providing a sound scientific and technical basis for regulatory policies based on air quality models to improve ambient air quality. The models developed by AMAD are being used by EPA, NOAA, and the air pollution community in understanding and forecasting not only the magnitude of the air pollution problem, but also in developing emission control policies and regulations for air quality improvements.
Description:
Ensemble forecasting has been used for operational numerical weather prediction in the United States and Europe since the early 1990s. An ensemble of weather or climate forecasts is used to characterize the two main sources of uncertainty in computer models of physical systems: (i) initial conditions and forcing variables (i.e., parametric uncertainty); and (ii) imperfections in the formulation of the physical model, such as those due to mathematical approximations or lack of understanding about the fundamental mechanisms underlying the physical process (i.e., structural uncertainty).