Reanalysis precipitation products (RPPs) are frequently used for studying the water cycle changes from short to long-term scale globally. In the current study, ERA-5 produced by the European Centre for Medium-Range Weather Forecasts (ECMWF), the Japanese 55-year Reanalysis (JRA-55), the Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2), and the Climate Forecast System version 2 (CFS-2) precipitation products were evaluated with the rain-gauge data as a reference during 1981–2019 over Pakistan. The performance was assessed using statistical error metrics on daily, monthly, and annual timescales. The reanalysis precipitation products (RPPs) captured the precipitation intensities and the extreme precipitation events (75th to 99th percentile) across climatic classes. On a daily scale, the ERA-5 follows rain-gauges very closely (RC: 0.67, R: 0.81, RMSE: 1.69 mm), consistently capturing the precipitation intensities (light to violent) and extreme precipitation events (95th percentile), followed by CFS-2. The MERRA-2 captured precipitation intensity but did not detect extreme precipitation events in some regions. The JRA-55 produced good results in the central area while overestimated the precipitation in the northern and southern parts of the study area. On a monthly time scale, ERA-5 performed well as compared to the rest of RPPs, with regression coefficient values of 0.91, correlation coefficient (0.96), and a lower value of RMSE (11.09 mm), followed by JRA-55, MERRA-2, and CFS-2. All the RPPs performed better in winter, pre-monsoon, and post-monsoon seasons with slight deviations/differences, but in monsoon season, the ERA-5 and JRA-55 (MERRA-2, CFS-2) overestimated (underestimated) precipitation mean. The findings can help the researchers select reliable datasets for bias correction of the projections and real-time application in flood, drought estimation, and prediction.

再分析降水产品 (RPP) 经常用于研究全球范围内从短期到长期的水循环变化。在当前的研究中，由欧洲中期天气预报中心 (ECMWF) 制作的 ERA-5、日本 55 年再分析 (JRA-55)、现代研究和应用回顾性分析第 2 版 (MERRA- 2) 和气候预测系统第 2 版 (CFS-2) 降水产品，以 1981-2019 年间巴基斯坦的雨量计数据作为参考进行评估。使用每日、每月和每年的时间尺度上的统计误差指标来评估性能。再分析降水产品 (RPP) 捕获了跨气候类别的降水强度和极端降水事件（第 75 至 99 个百分点）。在每天的规模上，RC：0.67，R：0.81，均方根误差: 1.69 mm)，持续捕捉降水强度（轻到猛烈）和极端降水事件（第 95 个百分位数），其次是 CFS-2。MERRA-2 捕捉到了降水强度，但没有检测到某些地区的极端降水事件。JRA-55在中部地区产生了良好的结果，而高估了研究区北部和南部的降水量。在每月时间尺度上，ERA-5 与其他 RPP 相比表现良好，回归系数值为 0.91，相关系数为 (0.96)，RMSE 值较低 (11.09 mm)，其次是 JRA-55、MERRA -2 和 CFS-2。所有 RPP 在冬季、季风前和季风后都表现较好，但略有偏差/差异，但在季风季节，ERA-5 和 JRA-55（MERRA-2，CFS-2) 高估（低估）降水平均值。这些发现可以帮助研究人员选择可靠的数据集，以对预测进行偏差校正，并在洪水、干旱估计和预测中实时应用。