Spatial and Seasonal Variability of Precipitation in Napo Province Using ERA5 Data (2000–2024)
Keywords:
Ecuadorian Amazon, climatology, seasonality, precipitation, ERA5 reanalysisAbstract
The Andean–Amazonian relief makes precipitation difficult to represent in areas with sparse weather-station coverage. This study characterized the spatial and seasonal variability of precipitation in Napo Province, Ecuador, from 2000 to 2024 using ERA5 reanalysis. Daily totals from 17 grid cells at 0.25° located within the provincial boundary were processed to calculate monthly and seasonal climatologies, descriptive statistics, and the Walsh and Lawler Seasonality Index. Mean provincial annual precipitation was 3,451.45 mm, with a standard deviation of 407.60 mm and a coefficient of variation of 11.81%. The wettest year was 2018 (4,209.84 mm), whereas 2002 had the lowest total (2,810.53 mm). March–April–May was the wettest season (1,048.62 mm), while September–October–November was the least rainy (752.97 mm). The Seasonality Index was 0.139, indicating a highly uniform distribution of rainfall throughout the year. Spatially, annual averages ranged from 1,927.50 to 5,420.95 mm, revealing a gradient related to the transition between Andean slopes and Amazonian lowlands. The results provide a reproducible baseline for water and land management, although they should be interpreted considering reanalysis limitations over complex terrain.
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