Abstract: Satellite precipitation products, as a new data source for estimating rainfall and runoff in watersheds with sparse or no data, still require extensive experiments to evaluate their applicability. This study systematically evaluated the accuracies of 4 satellite precipitation products, i.e. TRMM(3B42V7), TRMM_RT(3B42V7), PERSIANNCDR, and CMORPH, in calculating catchmentaveraged rainfall and simulating runoff for the Huanshui RiverHuayuan watershed; the applicability and reliability of each precipitation product were thoroughly examined by postulating multiple plans and hydrological scenarios. Results indicate that: (1) None of the 4 tested satellite precipitation products is consistently optimal in all plans/scenarios during the study period 20022013, whilst the performance of PERSIANN product is always the worst; (2) Differences in the accuracy of satellite precipitation products in different years and statistical periods are distinct, and the accuracy in flood period is higher than that for the whole year. The correlation coefficients between satellitebased rainfall data (derived from the most accurate satellite precipitation product in each year) and the gauge rainfall data are higher than 0.9 at annual and floodperiod time scales; (3) Satellite precipitation products present good performance in rainfall estimation during rainy days, though with relatively high nohitting rates. All satellite precipitation products show relatively bigger error in estimating annual maximum 1day, 3day, and 7day precipitation amounts, failing to meet the required precision for applications; (4) For runoff simulations, calibrating hydrological model parameters based on the corresponding product would achieve higher accuracy. TRMM_RT and CMORPH products are more accurate in daily runoff simulations, while CMORPH product outperforms in monthly runoff simulations. In conclusion, CMORPH product is more applicable for runoff simulation. As suggested by the simulations of 3 typical flood events, TRMM_RT and CMORPH products are of higher accuracy in simulating flood peak and volume (runoff depth).

Key words: satellite precipitation estimation, runoff simulation, Huayuan catchment, Xin’anjang hydrological model