Validation of Global Precipitation Data Sets to Runoff Generation Using Swat Modeling System
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Date
2015-12
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Addis Ababa University
Abstract
The main objective of this study is to evaluate the performance of globally gridded high – resolution satellite rainfall products (TMPA 3B42V7, Corrected coarse CMORPH, and Adj-PERSIANN) under sparse ground based data and complex topography of Angar Watershed (3627.6 km2) in Upper Nile basin Ethiopia through semi-distributed hydrological model SWAT for monthly streamflow simulation.
The model is calibrated for the period of 2003 – 2007 and validated for the period of 2008 – 2010. Comparisons of the simulations to the observed streamflow at the outlet of Angar Watershed form the basis for the conclusions of this study. The Nash-Sutcliffe Efficiency (NSE), Coefficient of Determination (R2), Root Mean Square Error (RMSE), linear correlation coefficient (R) and BIAS indices were used to benchmark the model performance.
Our results reveal that the performance of the satellite rainfall products as input to SWAT for monthly stream flow simulation strongly depends on the product type. Simulation from all rainfall inputs captured the trend of observed hydrograph. Simulation based on the new version of TMPA 3B42V7 and CMORPH showed consistent and modest skills in their simulations but slightly overestimates the large flood peaks in some years (2005 & 2006). On the other hand, the infrared – based algorithm PERSIANN simulation showed poor skills in reproducing the hydrograph at the outlet of the watershed. One of the reasons may be due to PERSIANN product is relatively less correlated to observed rainfall and other satellite products.
Overall, the results indicate that although some uncertainties exist in these gridded datasets (3B42V7 & CMORPH), the application of these gridded data prove useful for hydrological studies in the absence of station data. It strongly indicates the growing potential of the predictive accuracy of the satellite rainfall products in reproducing hydrological features.
Key words: Satellite rainfall products, SWAT model, Angar watershed
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Keywords
Satellite rainfall products, SWAT model, Angar watershed