###### Abstract  
Satellite precipitation products from the Global Precipitation Measurement (GPM) mission and its predecessor the Tropical Rainfall Measuring Mission (TRMM) are a critical data source for hydrological applications in ungauged basins. This study conducted an initial and early evaluation of the performance of the Integrated Multi-satellite Retrievals for GPM (IMERG) final run and the TRMM Multi-satellite Precipitation Analysis 3B42V7 precipitation products, and their feasibility in streamflow simulations in the Chindwin River basin, Myanmar, from April 2014 to December 2015 was also assessed. Results show that, although IMERG and 3B42V7 can potentially capture the spatiotemporal patterns of historical precipitation, the two products contain considerable errors. Compared with 3B42V7, no significant improvements were found in IMERG. Moreover, 3B42V7 outperformed IMERG at daily and monthly scales and in heavy rain detections at four out of five gauges. The large errors in IMERG and 3B42V7 distinctly propagated to streamflow simulations via the Xianjiang hydrological model, with a significant underestimation of total runoff and high flows. The bias correction of the satellite precipitation effectively improved the streamflow simulations. The 3B42V7-based streamflow simulations performed better than the gauge-based simulations. In general, IMERG and 3B42V7 are feasible for use in streamflow simulations in the study area, although 3B42V7 is better suited than IMERG. GPM; IMERG; TRMM; TMPA; satellite precipitation; hydrological modeling; Xianjiang hydrological model 2017 930201039  
Sensed Information using Artificial Neural Network [2], the Climate Precipitation Center morphing method (CMORPH) [3], the Global Satellite Mapping of Precipitation [4], and Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) [5], have been developed. Among them, TRMM TMPA products have been widely used for hydrological applications [6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24]. Developed by the Goddard Space Flight Center of the National Aeronautics and Space Administration (NOAA), the TRMM TMPA provides precipitation products derived from multiple satellites through a calibration-based sequential scheme and monthly gauge analyses, where feasible, on a high spatiotemporal resolution (0.25\({}^{\circ}\)\(\times\) 0.25\({}^{\circ}\) and three-hour interval) covering the latitude belt from 50\({}^{\circ}\)N to 50\({}^{\circ}\)S [5]. Its post-real-time products (versions 6 and 7, hereafter referred to as 3B42V6 and 3B42V7) have been widely used in hydrological applications worldwide, such as Italy [6; 7; 8], the USA [9; 10; 11], Tunisia [12], Wangchu basin in Bhutan [13], Mod basin in India [16], La Plata basin [18] and Andean-Amazon River [19] in South America, Laohahe basin [20; 21] and Tibetan Plateau [22] in China, Volta and Baro-Akobo basins [23] in Africa, and the mountainous region in South Korea [24]. These studies proved that TMPA 3B42 products have acceptable or even satisfactory hydrological prediction capabilities. TRMM was decommissioned on 8 April 2015 after more than 17 years of data gathering. The spacecraft reentered the Earth's atmosphere on 15 June 2015 over the South Indian Ocean. Meanwhile, the TMPA products will continue to be produced up to early 2018 [25]. As the successor of TRMM, the Global Precipitation Measurement (GPM) mission was officially launched on 27 February 2014. GPM was designed to obtain global satellite precipitation estimates based on an international satellite constellation [26]. The newly released Integrated Multi-satellite Retrievals for GPM (IMERG) [27] provide global precipitation products at finer spatiotemporal scales (0.1\({}^{\circ}\)\(\times\) 0.1\({}^{\circ}\) and 30-min interval) and with more expansive quasi-global coverage (60\({}^{\circ}\)N-60\({}^{\circ}\)S) than current TMPA products. As an extension and upgrade of TMPA, IMERG is currently in the initial evaluation phase. [PERSON] et al. [27] and [PERSON] et al.