Retrieval of suspended sediment concentrations in the turbid water of the Upper Yangtze River using Landsat ETM

For the remote areas like the Longitudinal Range-Gorge Region (LRGR), it is hard to measure the suspended sediment concentrations (SSC). This study attempted to estimate SSC by employing the three atmospheric correction methods: COST, iCOST (modified from COST) and TZB5 (newly proposed). TZB5 can more accurately determine the atmospheric transmittance along the sun-ground surface path (TAUz) from the solar zenith angle (TZ), and it uses Band 5 to eliminate the path radiance of Bands 1-4. The water surface reflectance at Band 4 obtained using TZB5 has a stronger relation with SSC within the range of 0-3000 mg/L. The developed algorithms could accurately estimate SSC directly from ETM+ images in the turbid Upper Yangtze River, and were also effective in the Middle Yangtze River.