## 1 Introduction
IMERG provides global precipitation estimates at finer spatiotemporal scales (0.1\({}^{\circ}\)\(\times\) 0.1\({}^{\circ}\) and 30-min interval) and more expansive quasi-global coverage (60\({}^{\circ}\)N-60\({}^{\circ}\)S) than TMPA products [26]. IMERG includes three products with different latencies: the near-real-time \"Early\" and \"Late\" run (IMERG-E and IMERG-L, respectively) and the post-real-time \"Final\" run (IMERG-F) [26]. Many previous studies demonstrated that IMERG SPPs generally present a relatively higher accuracy in comparison with TMPA in many regions, such as the compromising USA [27; 28], Brazil [29], West and East Africa [30], the northern highlands of Pakistan [31], Malaysia [32], India [33; 34], the Mekong River basin [35; 36], Iran [37; 38], South Korea [39], Japan [39], Mainland China [40; 41], the Qinghai-Tibet Plateau [42; 43], the Beijing River basin [24], the Mishui basin [25], and the Yellow River source region [44] of China. Not many previous studies [24; 25; 36; 44; 45; 46; 47; 48; 49; 50] have evaluated the performance of IMERG in streamflow simulations at the basin scale because it has only been released for four years. For instance, in the Ganjiang River basin of China, [PERSON] et al. [45] highlighted that IMERG-F version 03 (V03) performs similarly to the ground precipitation data in daily discharge simulations and outperforms TMPA version 7 (V7) near-real-time product (3B42 RT) and post-real-time product with gauge-based bias-correction (3B42V7) in many cases. [PERSON] et al. [46] further proved that the gauge-corrected radar precipitation estimates and rain-gauge-interpolated data exhibit better hydrological performance in hourly streamflow simulations in the Ganjiang River basin compared with IMERG-F V03. [PERSON] et al. [47] demonstrated that IMERG-F V03 and 3B42V7 are feasible in daily discharge simulations in the Chindwin River basin in Myanmar, in which 3B42V7 is more suitable than IMERG-F in terms of Nash-Sutcliffe model efficiency coefficient (NSE) and relative bias of total runoff. In the Beijing River basin of China, the variable infiltration capacity model-based daily streamflow simulations showed that IMERG-F V03 has high accuracy and good hydrological utility, IMERG-E and IMERG-L have satisfactory hydrological utility during the flood season, and IMERG-F generally outperforms 3B42V7 [24]. [PERSON] et al. [48] indicated that IMERG-F V03 is as useful as 3B42V7 and 3B42 RT in simulating daily streamflow in the southern regions of the Peruvian\(-\)Ecuadorian Amazon basin, but none of the three SPPs properly simulate streamflow in the northern regions. [PERSON] et al. [44] concluded that IMERG-F version 05 (V05) and 3B42V7 are feasible for 3-hourly flood simulations in the Yellow River source region of China, and IMERG-F is better suited than 3B42V7, with the IMERG-F-based simulation runs presenting higher NSEs and lower systematic biases of total runoff relative to the 3B42V7-driven model runs. In the Mishui basin of China, IMERG-F V05 demonstrates the best performance in daily streamflow simulation, and IMERG-E presents comparable performance to that of 3B42V7 [25]. Most of these studies [24; 25; 36; 44; 45; 48] indicated that IMERG improves hydrological utilities over TMPA standard products owing to its enhanced precipitation retrievingtechniques. However, most relevant studies [24; 25; 36; 45; 47; 48; 50] focused on assessing the hydrological utility of IMERG at daily or monthly time scales, while evaluations at sub-daily temporal scales have seldom been reported [44; 46; 49]. Furthermore, studies on the hydrological performance of all the \"Early\", \"Late\", and \"Final\" runs of IMERG are rare [24; 25; 50]. Focusing on the hydrological utilities of IMERG in near- and post-real-time versions at sub-daily temporal scales is necessary, considering that near-real-time SPPs in fine spatiotemporal resolutions and short latencies are expected to be reliable precipitation data sources for flood forecasting and monitoring.