Work

Estimation of High-Resolution Soil Moisture Using Sentinel-1 and LightGBM over the Miho River Watershed

Year: 2025

Type: article

Abstract: Soil moisture is a key variable mediating hydrological and energy exchanges between the land surface and atmosphere, and plays an important role in hydrometeorology and disaster management. Although various in-situ observation networks have been established, their spatial representativeness is limited. In this study, high-resolution soil moisture was estimated over the Miho River watershed using Sentinel-1 and the Light Gradient Boosting Model (LightGBM). A time-series analysis between Sentinel-1 C-band backscatter coefficients and soil moisture showed that the vertical-vertical polarized backscatter (σVV) responded more sensitively to soil moisture changes than the vertical-horizontal polarized backscatter (σVH). The statistical evaluation of the LightGBM-based soil moisture estimation yielded a correlation coefficient of 0.722 and a root mean square error of 4.69%. SHapley Additive exPlanation analysis indicated that the day of the year had the highest importance, and σVV showed greater importance than σVH. The spatial distribution of soil moisture revealed high soil moisture (25-40%) in cropland and grassland areas immediately after rainfall, whereas forest areas exhibited more gradual variation owing to canopy interception and shading effects.

Source: Korean Society of Hazard Mitigation

DOI: 10.9798/kosham.2025.25.6.65

Authors: Jongmin Park, Kijin Park, Yangwan Kim, Byung-kyu Kim

Institution: Korea Railroad Research Institute

Language: English

Topic: Soil Moisture and Remote Sensing

Subfield: Environmental Engineering

Field: Environmental Science

Domain: Physical Sciences

SDGs: Life on land, Climate action, Zero hunger

Open Access status: diamond

Funders: Ministry of Education, Ministry of Environment, Korea Railroad Research Institute, Korea Environmental Industry and Technology Institute