Evaluation of future precipitation scenario using statistical downscaling model over humid, subhumid, and arid region of Nepal—a case study
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Statistical downscaling model (SDSM) was applied in downscaling precipitation in the three climatic regions of Nepal. The study includes the calibration of the SDSM model by using large-scale atmospheric variables encompassing National Centers for Environmental Prediction (NCEP) reanalysis data, the validation of the model, and the outputs of downscaled scenarios A2 and B2 of the HadCM3 model for the future. The average R 2 value during validation period was 0.84, indicating the good applicability of SDSM for simulating precipitation. Under both scenarios A2 and B2, during the prediction period of 2010–2099, the change of annual mean precipitation in the three climatic regions would present a tendency of surplus of precipitation as compared to the mean values of the base period. On the average for all three climatic regions of Nepal, the annual mean precipitation would increase by about 13.75 % under scenario A2 and increase near about 11.68 % under scenario B2 in the 2050s. The model showed better performance over humid region; moreover, simulated results for the peak monsoon months seem to be overestimated over subhumid and arid regions.
KeywordsBias Correction Base Period Future Period Validation Period Dynamical Downscaling
We would like to thank Robert L. Wilby and Rashid Mahmood for suggesting on the queries about the SDSM methodology. Similarly, we acknowledge the Department of Hydrology and Meteorology of Nepal for providing the station data. This research was funded by the Chinese Academy of Sciences (XDB03030201), The CMA Special Fund for Scientific Research in the Public Interest (GYHY201406001), the National Natural Science Foundation of China (91337212, 41275010) and EU-FP7 Projects of "CORE-CLIMAX" (313085).
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