Hydroclimate variability and long-lead forecasting of rainfall over Thailand by large-scale atmospheric variables |
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| Authors: | Nkrintra Singhrattna Sylvain R Perret |
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| Institution: | 1. Water Engineering and Management , Asian Institute of Technology , Pathumthani , Thailand nkrintras@yahoo.com;3. Water Engineering and Management , Asian Institute of Technology , Pathumthani , Thailand;4. Centre de Coopération Internationale en Recherche Agronomique pour le Développement, UMR G-Eau , Montpellier , France |
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| Abstract: | Abstract The development of statistical relationships between local hydroclimates and large-scale atmospheric variables enhances the understanding of hydroclimate variability. The rainfall in the study basin (the Upper Chao Phraya River Basin, Thailand) is influenced by the Indian Ocean and tropical Pacific Ocean atmospheric circulation. Using correlation analysis and cross-validated multiple regression, the large-scale atmospheric variables, such as temperature, pressure and wind, over given regions are identified. The forecasting models using atmospheric predictors show the capability of long-lead forecasting. The modified k-nearest neighbour (k-nn) model, which is developed using the identified predictors to forecast rainfall, and evaluated by likelihood function, shows a long-lead forecast of monsoon rainfall at 7–9 months. The decreasing performance in forecasting dry-season rainfall is found for both short and long lead times. The developed model also presents better performance in forecasting pre-monsoon season rainfall in dry years compared to wet years, and vice versa for monsoon season rainfall. Editor Z.W. Kundzewicz Citation Singhrattna, N., Babel, M.S. and Perret, S.R., 2012. Hydroclimate variability and long-lead forecasting of rainfall over Thailand by large-scale atmospheric variables. Hydrological Sciences Journal, 57 (1), 26–41. |
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| Keywords: | rainfall hydroclimate variability ENSO large-scale atmospheric variables long-lead forecasting statistical approach modified k-nn model cross-validated multiple regression Chao Phraya River Basin Ping River Basin Thailand |
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