## 5 Discussion
### Evaluation of Hydrological Performance of the GPM-Era SPPs  
A few recent studies have been conducted to evaluate the hydrological utilities of the GPM-era SPPs in several basins in the world (Table S2). The three main findings are generalized in this table: (1) IMERG-F is generally superior to 3B42V7 in hydrological simulations in many regions owing to its enhanced precipitation estimates; (2) the IMERG post-real-time product (IMERG-F) tends to have better hydrological abilities than the near-real time products (IMERG-E and IMERG-L); and (3) although a few previous studies show that the earlier versions of GSMaP are feasible for flash flood simulations [10; 51] and flood inundation modeling [9; 55], the hydrological evaluations of the latest GPM-era versions of the GSMaP products were seldom reported in recent studies. Although Section 4.2 only demonstrates the hydrological performance of the best near-real-time SPP (3B42 RT) and the comparatively better post-real-time SPPs (IMERG-F and 3B42V7), our study also evaluated the hydrological utility of the other five SPPs (IMERG-E, IMERG-L, GSMaP-NRT, GSMaP-MVK, and GSMaP-GAUGE), which is summarized in Table S2. Our study found that IMERG-F V05 and 3B42V7 have acceptable hydrological capabilities in the Chindwin River basin, with IMERG-F being slightly better than 3B42V7. Similar findings were reported in the Ganjiang River basin [45], Beijing River basin [24], upper Mekong River basin [36], Mishui basin [25], Yellow River source region of China [44], and Amazon basin of Peru and Ecuador [48]. [PERSON] et al. [47] employed the first hydrological evaluation research in the Chindwin River basin and found that IMERG-F V03 performs comparatively worse than 3B42V7 in daily streamflow simulations. In comparison with [PERSON] et al. [47], our study demonstrates that the updated precipitation retrieval algorithms (V05B) effectively enhanced the hydrological utility of IMERG-F in the study area. Moreover, our study generally agrees with the findings of several previous studies [24; 25; 50] that IMERG-F with the rain-gauge-adjustment has better hydrological performance than IMERG-E and IMERG-L. In the Mishui basin of China, [PERSON] et al. [25] found that IMERG-E presents better daily hydrological performance than 3B42 RT, even comparable to 3B42V7. Our study displays that all near- and post-real-time products of IMERG present poorer hydrological abilities than TMPA near-real-time product 3B42 RT, mainly because 3B42 RT has the best quality among all the evaluated SPPs. Moreover, our work is also among the early attempts to evaluate the hydrological performance of the latest GPM-era GSMaP products. Compared with IMERG, GSMaP presents unsatisfactory flood simulation capabilities in near- and post-real-time cases in the Chindwin River basin; these outcomes are mainly caused by their inferior precipitation retrievals. Specifically, the quality of satellite precipitation retrievals predominantly affects their hydrological utilities. The findings of this study emphasize the need for the GPM technical community to further refine the algorithms and enhance the accuracy of the IMERG and GSMaP products in Myanmar. In particular, the expected enhanced near-real-time SPPs would be promising for effective real-time flood forecasts and warnings in large ungauged watersheds, which would be helpful for local flood control and damage mitigation, considering that the latency of the near-real-time products is short (e.g., 4 h for IMERG-E and GSMaP-NRT). Notably, this study demonstrates the overall quality and hydrological feasibility of multiple SPPs in the period from 1 April 2014 to 31 December 2016. It is very possible that SPPs might have various performance in retrieving precipitation in different time periods. Thus, future work will focus on dividing the evaluation period into pre-, mid-, and post-monsoon seasons and assessing the quality and hydrological utility of SPPs in these sub-periods, respectively.