**5. Conclusions**

In this study, the performance of SM2RAIN-CCI and SM2RAIN-ASCAT were assessed extensively across Pakistan using the rain gauge (RGs) observations. The assessment was carried across four different climate regions of Pakistan, namely glacial, humid, arid and hyper-arid regions during the period 2000–2015 (for SM2RAIN-CCI) and 2007–2015 for (SM2RAIN-ASCAT) on a daily scale. Three statistical metrics, i.e., Bias (%), ubRMSE (mm/day), and Theil's U coefficient, and four categorical metrics, i.e., POD, FAR, CSI and Bias score, were used to assess the performance of SM2RAIN-based products. Moreover, the total mean square error was also decomposed to random and systematic error components, while KGE was also used to evaluate the performance of PPs. Finally, SM2RAIN-CCI and SM2RAIN-ASCAT were compared and evaluated against an extensively evaluated satellite precipitation product, i.e., TRMM TMPA 3B42 v7 (TMPA). Based on the results, following conclusions were drawn:


(9) Comparison of SM2RAIN-based products with TMPA revealed the better performance of TMPA across all climate regions in terms of all statistical metrics.

**Author Contributions:** K.U.R. and S.S. conceived the research topic and formulated the methods; K.U.R. and M.S. collected and arranged the data, K.U.R. and Y.W. performed data processing and analysis, K.U.R. and S.S. interpreted the results, K.U.R. wrote the paper, S.S., M.S. and Y.W. provided reviews and revised manuscript.

**Funding:** This research was partially supported by the National Natural Science Foundation of China (grant numbers 51779119 and 51839006).

**Acknowledgments:** The authors would like to thank the Pakistan Meteorological Department (PMD) and Water and Power Development Authority (WAPDA) for providing the gauge based precipitation records and grateful to the developers of SM2RAIN-based precipitation products. The authors are thankful to editor and anonymous reviewers for their insightful comments and constructive suggestions, which have substantially improved the quality of the paper.

**Conflicts of Interest:** The authors declare no conflicts of interest.
