Aligning Evapotranspiration from MOD16A2.061 Product to Ground Estimates in Piemonte (NW Italy): an analysis of temporal and spatial biases
Evapotranspiration (ET), and in particular Reference Evapotranspiration (ET<sub>0</sub>), is essential for agricultural planning, irrigation management, and water resource allocation—especially in regions facing water scarcity and limited observational data. While ground-based...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2025-05-01
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| Series: | The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences |
| Online Access: | https://isprs-archives.copernicus.org/articles/XLVIII-M-7-2025/201/2025/isprs-archives-XLVIII-M-7-2025-201-2025.pdf |
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| Summary: | Evapotranspiration (ET), and in particular Reference Evapotranspiration (ET<sub>0</sub>), is essential for agricultural planning, irrigation management, and water resource allocation—especially in regions facing water scarcity and limited observational data. While ground-based ET<sub>0</sub> is typically estimated using the FAO Penman-Monteith method, satellite-derived products such as MOD16 offer broader spatial coverage, although with conceptual and methodological differences. MOD16 provides Potential Evapotranspiration (PET) estimates, which, unlike ET<sub>0</sub>, depend on local biome characteristics and are not standardized to a reference surface.<br />This study investigates whether the PET data from the MOD16A2GF product (version 6.1) can be adapted for ET<sub>0</sub> estimation in Piemonte (NW Italy), a region characterized by diverse climates and topographies. We compared PET data from 2010 to 2022 with ground-based ET<sub>0</sub> and applied a bias-correction method using linear regression models calibrated on local meteorological time series. The corrected dataset (<em>ÊT</em><sub>0</sub>) shows significantly improved agreement with ground-based ET<sub>0</sub>, reducing the Mean Absolute Error from 10.06 mm/8 d to 2.48 mm/8 d, a 75% improvement. This correction proved robust across the region and particularly effective during the summer, when accurate ET<sub>0</sub> estimation is critical for crop irrigation.<br />Our results suggest that, with appropriate local calibration, MOD16A2GF PET data can serve as a practical surrogate for ET<sub>0</sub> in data-scarce environments. Future research should focus on exploring the impact of additional factors, such as altitude and land cover variability, to further refine the accuracy of satellite-derived ET<sub>0</sub> estimates and improve their applicability in diverse climatic and topographical conditions. |
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| ISSN: | 1682-1750 2194-9034 |