## 1 Introduction
Another prevailing satellite-based global precipitation monitoring project in the TRMM and GPM eras is GSMaP, which was supported by the Core Research for Evolutional Science and Technology of the Japan Science and Technology Agency and promoted by the JAXA Precipitation Measuring Mission (PMM) science team [6]. The GSMaP algorithm combines information from TRMM and other satellites to produce high-resolution (0.1\({}^{\circ}\)\(\times\) 0.1\({}^{\circ}\), 1 hourly) global precipitation products over the 60\({}^{\circ}\)N-60\({}^{\circ}\)S domain [6]. As the Japanese partner of GPM, the JAXA PMM science team recently updated the GSMaP algorithm for the GPM mission by merging passive MW (PMW) radiometer data from GPM Core GMI. GSMaP provides a series of precipitation estimates with different latencies, such as near-real-time product (GSMaP-NRT), post-real-time product with MW-IR reanalysis (GSMaP-MVK), and gauge-corrected post-real-time product (GSMaP-GAUGE). These products have been used for hydrological applications, such as flash flood simulations in the Nile River basin in Egypt [51], the Huong River basin in Vietnam [52], the Karpuz River basin in Turkey [10], and the Jhelum, Chenab, and upper Indus River basins in Pakistan [53; 54]; flood inundation modeling in the Thua Thien Hue Province in Vietnam [55] and the Mundeni Aru River basin in Sri Lanka [9]; daily streamflow simulations in the Tocantins-Araguaia basin in Brazil [7], the Soyang dam basin in South Korea [56], and the Biliu basin in China [8]; annual runoff analysis in West Africa [57]; and global surface runoff mapping [58]. However, most of these studies [7; 8; 9; 10; 51; 52; 53; 54; 55; 56; 57] mainly adopted TRMM-era GSMaP SPPs (e.g., GSMaP versions 04 and 05) for hydrological evaluations or applications, and the hydrological assessment of GPM-era GSMaP SPPs (e.g., versions 06 and 07) was rarely reported. Since IMERG and GSMaP are two parallel SPPs for the GPM mission, these two products should be hydrologically evaluated and quantitatively compared in different regions of the world. This study evaluates two parallel GPM-era IMERG and GSMaP SPPs in comparison with TRMM-era TMPA products from the statistical and hydrological aspects in the poorly gauged Chindwin River basin in Myanmar (Figure 1). Given that few previous studies have focused on the statistical and hydrological evaluations of GPM-era IMERG and GSMaP SPPs in both near- and post-real-time versions at sub-daily time scales, the main goals of this study are as follows:  
1. statistically assess and compare the accuracy of the latest GPM-era IMERG (IMERG-E, IMERG-L, and IMERG-F) and GSMaP (GSMaP-NRT, GSMaP-MVK, and GSMaP-GAUGE) SPPs with that of the TRMM-era TMPA SPPs (3B42 RT and 3B42V7) at sub-daily time scales (3 h for daytime precipitation estimates and 12 h for nighttime precipitation retrievals) in the study area; and
2. comprehensively assess the hydrological performance of the latest GPM-era SPPs in simulating historical discharge processes at 3-h temporal scales in comparison with TMPA SPPs. This manuscript presents the first comprehensive study on the feasibility of the latest GPM-era SPPs in flood simulations in the Chindwin River basin. The findings reported in this manuscript are expected to provide SPP researchers with timely and useful feedbacks from the poorly gauged basin in Myanmar with regards to the quality of the latest GPM-era SPPs. This study also has the potential to provide valuable guidelines for the hydrological applications of SPPs in the Chindwin River basin.