This study evaluated the performance of three versions of Global Satellite Mapping of Precipitation (GSMaP) products at 0.1° spatial resolution for monitoring meteorological drought over Iran. The investigated GSMaP products included the gauge-corrected product (GSMaP-Gauge), the standard MW-IR combined product (GSMaP-MVK), and the near-real-time product (GSMaP-NRT), examined during the period from 1 March 2014 to 31 December 2018. For reference, we used highquality ground-observed precipitation data from 344 synoptic stations. The standard precipitation index (SPI) on diferent timescales from 1 to 12 months was used for the quantifcation of drought events. The statistical metrics employed for the assessment of the performance of the three GSMaP products included Pearson’s correlation coefcient (R) and root mean square error (RMSE). In addition to the evaluations based on spatial and temporal scales, the capability of the GSMaP products of identifying drought events was considered. The results indicated that GSMaP-Gauge was superior to the other two GSMaP products in the monitoring of drought patterns over Iran, with a much higher R and a much lower RMSE, particularly on long timescales. In spatial terms, all the three GSMaP products exhibited high performance in Western Iran, where precipitation is high. Generally, the study revealed the potential capability of GSMaP products for monitoring meteorological drought over Iran, particularly for data-poor or ungauged basins.
