Análisis comparativo de cuatro productos satelitales de precipitación mensual para la provincia de La Pampa

Abstract

Este estudio tuvo como propósito evaluar el desempeño de cuatro productos satelitales de precipitación mensual—CHIRPS, ERA5, GPM y JAXA GSMaP—en la provincia de La Pampa, Argentina, mediante su comparación con registros de pluviómetros. Se utilizaron datos de 26 estaciones meteorológicas con series completas o casi completas entre 2000 y 2025.

This study aimed to evaluate the performance of four satellite-based monthly precipitation products—CHIRPS, ERA5, GPM, and JAXA GSMaP—over La Pampa Province, Argentina, by comparing them with ground-based rain gauge records. A dataset of 26 meteorological stations with complete or near-complete records from 2000 to 2025 was used as a reference. Satellite estimates were extracted with Google Earth Engine and averaged within an 11 km buffer around each station. Simple linear regression models were trained (2000-2020) and validated (2021-2025). Model accuracy was assessed using R2 , RMSE, standard error, and bias, complemented with monthly and regional analyses. At the provincial scale, all products showed moderate agreement with observations (R2 =0.58-0.69). Most products underestimated precipitation, except GPM which initially overestimated but significantly improved in the validation stage, reducing its bias from >60 % to <10 % and achieving the lowest RMSE (<30 mm). Seasonal analysis revealed systematic winter overestimations, especially for JAXA. Regionally, better performance was observed in the humid East compared to the arid West, where isolated convective events were poorly detected. Among the evaluated products, GPM showed the most robust and consistent performance, particularly in the eastern sector of La Pampa. However, in arid areas with scarce rainfall and weak station coverage, satellite data should be complemented with local observations, with CHIRPS and ERA5 serving as auxiliary sources.