**4. Discussions**

It was noted in Figure 1a that more (less) differences are observed between GSMaP7 (IMERG5 and IMERG6) and TRMM7 concerning the distribution of maximum precipitation over Taiwan. This might be because the land precipitation in GSMaP7 is adjusted using the CPC gauge-based analysis daily precipitation, while the land precipitation in TRMM7 and the IMERG products are adjusted using the GPCC gauge-based monthly precipitation [1,3,4]. In fact, by comparing the difference between the mean status of GSMaP7 (IMERG5 and IMERG6) and TRMM7 over a larger domain averaged during the summers of 2014–2017, we note that the difference between GSMaP7 and TRMM is also larger over Indochina (see Figure 10). In contrast, over the ocean areas of the Asian domain, larger differences can be found between IMERG5 and TRMM7.

**Figure 10.** (**a**) Mean seasonal precipitation averaged during the summers of 2014–2017, estimated by TRMM7, over the Asian domain (60◦E–180◦, 10◦S–40◦N). (**b**) is related to (**a**), except for the difference between IMERG5 and TRMM7. (**c**) is similar to (**b**), except for the difference between IMERG6 and TRMM7. (**d**) is similar to (**b**), except for the difference between GSMaP7 and TRMM7.

Consistent with Figure 10, IMERG5 also has the daily variations in oceanic precipitation area-averaged over the Asian domain, more different to TRMM7 (Figure 11b; 5 day running mean applied). In contrast, for the daily variations in land-averaged precipitation, GSMaP7 appears to differ the most from TRMM7 (Figure 11a; 5 day running mean applied). To support the above arguments, we further calculate Tcorr and RMSE based on the time series given in Figure 11a,b and show the results in Figure 11c. It is confirmed that: (1) GSMaP7 has a more clear difference to TRMM7 (i.e., smaller Tcorr and larger RMSE) over the land; and (2) IMERG5 has a more clear difference to TRMM7 over the ocean. This information is particularly important for studies that tend to use GPM products to replace TRMM7 for estimating the moisture budget over the Asian domain [49–52].

**Figure 11.** Time series of 5-day running averaged precipitation area-averaged over (**a**) the land and (**b**) the ocean of the Asian domain (60◦E–180◦, 10◦S–40◦N). The time series covered is from 2014 to 2017 JJAs (i.e., 368 days). (**c**) is based on (**a**,**b**), except for the calculation of Tcorr and RMSE between TRMM7 and the selected SPPs, including IMERG5 (red), IMERG6 (blue), and GSMaP7 (green).
