Temporal downscaling: a comparison between artificial neural network and autocorrelation techniques over the Amazon Basin in present and future climate change scenarios
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Several studies have been devoted to dynamic and statistical downscaling for both climate variability and climate change. This paper introduces an application of temporal neural networks for downscaling global climate model output and autocorrelation functions. This method is proposed for downscaling daily precipitation time series for a region in the Amazon Basin. The downscaling models were developed and validated using IPCC AR4 model output and observed daily precipitation. In this paper, five AOGCMs for the twentieth century (20C3M; 1970–1999) and three SRES scenarios (A2, A1B, and B1) were used. The performance in downscaling of the temporal neural network was compared to that of an autocorrelation statistical downscaling model with emphasis on its ability to reproduce the observed climate variability and tendency for the period 1970–1999. The model test results indicate that the neural network model significantly outperforms the statistical models for the downscaling of daily precipitation variability.
KeywordsAutocorrelation Autocorrelation Function Daily Precipitation Amazon Basin Statistical Downscaling
The present work was supported by the FAPESP grant 07/50145-4, and Jose A. Marengo was funded by the Brazilian Conselho Nacional de Desenvolvimento Cientifico e Tecnologico—CNPq. We are also grateful for the helpful comments made by anonymous reviewers.
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