Assessing the Correlation Between Spectral Indices and Land Surface Heat Fluxes by Remote Sensing Technology: A Case Study in Thai Binh Province, Red River Delta, Vietnam

This work primarily aimed to evaluate the relationship between land surface heat fluxes and landscape features using spectral indices. The assessment mainly focuses on the energy exchange between the land surface and the atmosphere, specifically the latent and sensible heat fluxes in an agricultural area. The study initially encompassed the entire study area, with subsequent emphasis specifically directed towards examining paddy rice fields. Significant correlations were found between surface heat fluxes and water-related spectral indices, including the Normalized Difference Water Index (G_NDWI) and the Normalized Difference Latent Heat Index (NDLI). The G_NDWI consistently demonstrates its effectiveness in capturing the general features of Earth’s surface across all land cover types, while NDLI proves to be effective in assessing crop-specific characteristics. Consequently, the integration of NDLI into Land Surface Temperature (LST) using the principle of Temperature Moisture Dryness Index (TMDI) showcases its potential to effectively evaluate variations in the water status of paddy fields by displaying a strong relationship with the energy transfer of the evapotranspiration process. Correlation coefficients exceeding − 0.8 were observed between latent heat flux and TMDI, offering valuable insights into crop health and contributing to the enhancement of agriculture water management practices. The findings of this study effectively overcome the challenges associated with direct investigation and the limited availability of measured data, which can be attributed to a sparse network of ground stations.