Assessing Climate Reanalysis Products in Tropical Lowlands: A Validation Study from Colombian Oil Palm Regions

Abstract Recent technological advancements and data assimilation techniques have elevated the precision of weather reanalysis, creating detailed historical atmospheric gridded datasets by combining diverse observational data and numerical models. This study assessed the ERA5-Land and NASA Power climate reanalysis products in tropical lowlands, using data from 44 ground weather stations in Colombian oil palm production zones from 2008 to 2022. Validation results varied based on variables, locations, and temporal resolutions, with each product showing distinct strengths. ERA5-Land demonstrated superior performance in temperature estimation, while NASA Power excelled in solar radiation estimates. Despite the tropical setting, proximity to mountainous terrain created challenging microclimates, impacting reanalysis accuracy particularly for rainfall and relative humidity. Temporal data aggregation from daily to monthly and annual scales revealed varying patterns of improvement across variables, with some metrics showing enhanced performance at coarser temporal resolutions while others remained relatively unchanged. The study emphasizes the importance of careful product selection based on the specific variable and temporal scale of interest, especially in regions with complex microclimates or unique environmental conditions. While reanalysis data offer valuable insights, their limitations must be acknowledged to ensure accurate interpretation and application in research endeavors, particularly in tropical agricultural contexts.