2.2.3. Tropical Rainfall Measuring Mission

The Tropical Rainfall Monitoring Mission (TRMM) is a joint project between the NASA and the Japan Aerospace Exploration Agency (JAXA). The TRMM was launched on 27th November, 1997 [20,29,55]. It provides measurement for the intensity and areal coverage (60◦S to 60◦N) of tropical and subtropical precipitation, which covers about two third of the world's rainfall [38]. There is a range of orbital and gridded TRMM products available, i.e., 3B42RT and 3B43RT datasets [39]. Specifically, the daily rainfall (mm day−1) estimate from the TRMM (TMPA-RT) Near Real-Time Precipitation L3 1day 0.25◦ × 0.25◦ Version 7 (TRMM\_3B42RT\_Daily) is used as the primary dataset during the verification process in the present study, moreover, which is derived from the original three-hour averaged precipitation values available at https://giovanni.gsfc.nasa.gov/giovanni/#service=TmAvMp& starttime=&endtime=&dataKeyword=TRMM (Accessed on 20 June 2020). Further details can be found at https://disc.gsfc.nasa.gov/datasets/TRMM\_3B42RT\_Daily\_7/summary (Accessed on 20 June 2020). The daily TRMM\_3B42RT product (365 days) is aggregated into the annual total precipitation for the

year 2001, 2006 and 2012 (Figure 2l–n) and the average annual (2001–2015) precipitation (Figure 2o) @ 0.25◦ spatial resolution, which is used during the verification process. The equation deriving the annual total and the average annual precipitation is given in Equations (2) and (3), respectively.
