Navavit Ponganan. Development of a hybrid multisource soil moisture estimation framework (HMSMEF) using machine learning and remote sensing data. Doctoral Degree(Engineering and Technology). Thammasat University. Thammasat University Library. : Thammasat University, 2025.
Development of a hybrid multisource soil moisture estimation framework (HMSMEF) using machine learning and remote sensing data
Abstract:
Accurate, high-resolution soil moisture data is essential for optimizing agricultural water use and supporting environmental monitoring, particularly in rice cultivation areas with complex terrain and spatiotemporal variability. This study aims to develop a Hybrid Multisource Soil Moisture Estimation Framework (HMSMEF) that integrates advanced machine learning techniques with diverse remote sensing and auxiliary datasets to downscale SMAP soil moisture data to 10 m resolution. The framework synthesizes optical, radar, land use, precipitation, and topographic data through permutation testing of nine synergy combinations and applies three regression models: Random Forest (RF), Gradient Boosting (GB), and Classification and Regression Trees (CART). The optimal configurationSynergy 6, incorporating Sentinel-1 SAR, CHIRPS precipitation, and SRTM topographyachieved the best results using the CART model (R² = 0.927, RMSE = 0.005). Bias correction methods improved R² to 0.936, and a stacking ensemble of CART, RF, and GB further enhanced accuracy. Validation with two in-situ datasets showed strong performance: (1) 20182019 field data (R² = 0.91, RMSE = 5.35) for 1040 cm depth, with a widely sensor distance of 73 m ; and (2) 20212023 green manure plots (R² = 0.67 untreated, R² = 0.60 treated), with dense sensor spacing (6.8 m), reflecting local variability. HMSMEF demonstrates a scalable and robust solution for high-resolution soil moisture estimation, with significant implications for precision agriculture, sustainable water management, and environmental modeling.
Thammasat University. Thammasat University Library