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Advances in Meteorology
Volume 2012 (2012), Article ID 649450, 11 pages
http://dx.doi.org/10.1155/2012/649450
Research Article

A Neural Network Nonlinear Multimodel Ensemble to Improve Precipitation Forecasts over Continental US

1National Centers for Environmental Prediction, NOAA, College Park, MD 20740, USA
2Earth System Sciences Interdisciplinary Center, University of Maryland, College Park, MD 20740, USA

Received 26 May 2012; Accepted 31 July 2012

Academic Editor: Hann-Ming Henry Juang

Copyright © 2012 Vladimir M. Krasnopolsky and Ying Lin. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A novel multimodel ensemble approach based on learning from data using the neural network (NN) technique is formulated and applied for improving 24-hour precipitation forecasts over the continental US. The developed nonlinear approach allowed us to account for nonlinear correlation between ensemble members and to produce “optimal” forecast represented by a nonlinear NN ensemble mean. The NN approach is compared with the conservative multi-model ensemble, with multiple linear regression ensemble approaches, and with results obtained by human forecasters. The NN multi-model ensemble improves upon conservative multi-model ensemble and multiple linear regression ensemble, it (1) significantly reduces high bias at low precipitation level, (2) significantly reduces low bias at high precipitation level, and (3) sharpens features making them closer to the observed ones. The NN multi-model ensemble performs at least as well as human forecasters supplied with the same information. The developed approach is a generic approach that can be applied to other multi-model ensemble fields as well as to single model ensembles.