Multi-Mission Satellite Remote Sensing for Spatiotemporal Retrieval of Riverine Water Turbidity in the Chao Phraya River, Thailand
Teerawat Suwanlertcharoen*, Siam Lawawirojwong and Kampanat Deeudomchan

Geo-Informatics and Space Technology Development Agency (Public Organization), Thailand
*teerawat[at]gistda.or.th

Abstract

Riverine water turbidity is a key indicator of water quality, influencing light penetration, primary productivity, and the transport of sediments and pollutants, factors that directly affect aquatic ecosystems, public health, and water resource management. Given the dynamic nature of river systems, there is a growing need for accurate and timely methods to monitor turbidity over broad spatial and temporal scales. This study explores the potential of multi-mission satellite remote sensing for spatiotemporal retrieval of turbidity in the Chao Phraya River, a major waterway in Thailand that flows into the Gulf of Thailand. The research integrates multispectral data from Sentinel-2 (A and B), Landsat-8 and Landsat-9, and hyperspectral imagery from the EMIT mission by NASA. In-situ turbidity data from the Metropolitan Waterworks Authority (MWA) were used for algorithm development and validation. Atmospheric correction and sunglint removal were performed using the Dark Spectrum Fitting (DSF) algorithm in the ACOLITE software, chosen for its proven accuracy over inland and turbid waters. Surface reflectance in the red band was analyzed using a piecewise semi-empirical model employing polynomial and linear regression techniques. Validation against in-situ data showed strong agreement (R2 = 0.901, RMSE = 5.75 NTU, MAE = 4.68 NTU), demonstrating the effectiveness of the retrieval approach. The results reveal distinct spatiotemporal turbidity patterns along the river throughout 2024. This study confirms the robustness of multi-mission satellite remote sensing for turbidity monitoring and offers valuable insights for water quality management. The findings support informed decision-making for environmental protection and sustainable development, particularly given the influence of the river on the coastal ecosystems of the Gulf of Thailand.

Keywords: Riverine Water Turbidity, ACOLITE, Satellite Remote Sensing, Chao Phraya River, Piecewise Regression

Topic: Topic B: Applications of Remote Sensing