Evaluation of Precipitation Observations Across Ecuador

ABSTRACT Accurate precipitation observations are crucial for hydrological and climate monitoring, forecasting and research. However, sparse networks in regions with complex topography, like Ecuador, limit data availability. To address this gap, products such as ERA5 reanalysis, produced by ECMWF within the Copernicus Climate Change Service, and satellite‐based datasets, including IMERG (Integrated Multi‐satellite Retrievals for GPM) and MSWEP (Multi‐Source Weighted‐Ensemble Precipitation), offer near‐real‐time monitoring and spatial coverage in data‐scarce areas. This study evaluates these three precipitation products over Ecuador using quality‐controlled station data (1980–2024) to assess biases, extreme event detection, and the impact of topography. The results show that: (1) IMERG is the most skillful overall in estimating precipitation, particularly in lowland areas, though it declines in mountainous regions; (2) ERA5 and MSWEP underestimate precipitation in the Amazon, while ERA5 overestimates in high‐altitude regions; (3) during the 1998 El Niño event, all products had challenges in capturing localized heavy precipitation, although ERA5 consistently captured but overestimated coastal heavy precipitation; (4) For 99th percentile precipitation extremes, ERA5 overestimated precipitation by 5.0 mm/day, while IMERG overestimated by 2.5 mm/day. This study highlights the need to analyse high‐altitude precipitation estimates carefully and adapt bias‐adjustment methods, providing insights for climate monitoring in tropical mountain regions.