## 5 Conclusions  
In summary, the comparison of hourly precipitation data obtained from GPM IMERG and gauge observations revealed largely consistent spatial patterns of annual precipitation total but disparities in the patterns of annual precipitation frequency and intensity. The highest and lowest correlations between the two datasets for hourly precipitation were detected in North Asia (0.373, \(p<0.05\)) and Europe (0.308, \(p<0.05\)), respectively. Hourly precipitation intensity showed the largest RMSE (1.29 mm/h) in South Asia due to the strong precipitation intensity characterizing this region. IMERG was able to capture the bimodal structure of diurnal precipitation in South Asia but performed a small variation in North Asia. It generally overestimated precipitation at peak hours and underestimated it at trough hours, which resulted in larger fluctuations in the data compared with gauge observations. Both datasets showed similar patterns of interannual precipitation variability after the correction of the IMERG data using monthly ground observations, but IMERG overestimated the proportion of annual precipitation hours by 2.5% and 2.0% in North America and North Asia, respectively. These findings provide valuable insights for weather forecasting, the identification of extreme weather events, and climate change research.  
Conceptualization, G.W.; methodology, P.L. and G.W.; software, P.L.; validation, P.L.; formal analysis, P.L.; investigation, G.W.; resources, G.W.; data curation, G.W.; writing--original draft preparation, P.L. and G.W.; writing--review and editing, P.L. and G.W.; visualization, P.L.; supervision, G.W.; project administration, G.W.; funding acquisition, G.W. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China (42077421 and 41930970).  
The precipitation data of Integrated Surface Database (ISD) were downloaded from [[https://www.ncei.noaa.gov/products/land-based-station/integrated-surface-database](https://www.ncei.noaa.gov/products/land-based-station/integrated-surface-database)]([https://www.ncei.noaa.gov/products/land-based-station/integrated-surface-database](https://www.ncei.noaa.gov/products/land-based-station/integrated-surface-database)) (accessed on 14 June 2023). The hourly precipitation data from China Meteorological Administration (CMA) were available at [[http://data.cma.cn/en/7r=data/detail&dataCode=A.0012.0001](http://data.cma.cn/en/7r=data/detail&dataCode=A.0012.0001)]([http://data.cma.cn/en/7r=data/detail&dataCode=A.0012.0001](http://data.cma.cn/en/7r=data/detail&dataCode=A.0012.0001)) (accessed on 7 July 2023). The hourly precipitation data from the U.S. Climate Reference Network (USCRN) were available at [[https://www.ncei.noaa.gov/access/crn/](https://www.ncei.noaa.gov/access/crn/)]([https://www.ncei.noaa.gov/access/crn/](https://www.ncei.noaa.gov/access/crn/)) (accessed on 20 November2023). The GPM IMERG product data from 2001 to 2020 were downloaded at [[https://pmm.nasa.gov/data-access/downloads/gpm](https://pmm.nasa.gov/data-access/downloads/gpm)]([https://pmm.nasa.gov/data-access/downloads/gpm](https://pmm.nasa.gov/data-access/downloads/gpm)) (accessed on 13 January 2022).  
The authors declare no conflicts of interest.