Analysis of IMERG precipitation product in Mexican states to evaluate the spatial and temporal variation in precipitation

This study extensively assesses the performance of IMERG (Integrated Multi-satellitE Retrievals for Global Precipitation Measurement) satellite-based precipitation data in the Mexican states in relation to their potential applications in water resource planning and management. Through a detailed daily, monthly, and annual scale comparison between IMERG and CONAGUA’s ground-based weather stations, the research identified and discarded outliers in the weather stations data to enhance analytical reliability. Employing a state-by-state zonal analysis, the study evaluated the accuracy, trends, and percentage of change of IMERG precipitation records between 2001 and 2020. In particular, the leeward/windward mountain effect revealed to be a significant constraint on IMERG performance in mountainous regions, introducing uncertainties due to under/overestimation. The results propose the suitability of IMERG satellite precipitation product with varying levels of Spearman correlation coefficients of 0.85, 0.88 and 0.49, and RMSE of 364.7 mm/year, 62.4 mm/month and 9.9 mm/day at the annual, monthly, and daily scales, respectively. However, a more nuanced and state-specific exploration of the various satellite-based precipitation products is crucial to determine the optimal choice for water resource planning and management.