Comparison of flow simulations with sub-daily and daily GPM IMERG products over a transboundary Chenab River catchment

Abstract

Abstract This study proposes the assessment of SWAT model simulations, with the provision of satellite precipitation products (SPPs), in a transboundary/large catchment. Three latest sub-daily/half-hourly (HH) and daily (D) SPPs, i.e., ‘IMERG-E’, ‘IMERG-L’, and ‘IMERG-F’, were evaluated for daily and monthly flow simulations. The study revealed that monthly flow simulation performance is better than daily flow simulation in all sub-daily and daily SPPs-based models. Results depict that IMERG-HHF and IMERG-DF yield the best performance among the other latency levels of SPPs. The IMERG-HHF model has a reasonably higher daily correlation coefficient (R) and lower daily root-mean-square error (RMSE) than IMERG-DF. IMERG-HHF displays the lowest percent bias (PBIAS) values of 15.4 and 2.4 for daily and monthly flow validation, respectively. It also represents relatively higher values of coefficient of determination (R2) and Nash–Sutcliffe Efficiency (NSE) than any other model, i.e., R2=0.66 and NSE=0.63 for daily model validation and R2=0.84 and NSE=0.82 for monthly model validation. Moreover, the sub-daily IMERG model outperformed the daily IMERG model for all calibration and validation scenarios. The IMERG-DL model demonstrates poor performance in all of the SPPs, in daily and monthly validation, with low R2 (0.63 (dval) and 0.81 (mval)), low NSE (0.50 (dval) and 0.67 (mval)), and high PBIAS (31 (dval) and 26.6 (mval)). Additionally, the IMERG-HHE model outperformed IMERG-HHL.