Fig. 7

Validation of TSM and SDD Models: This figure compares measured and derived values for TSM and SDD models, with the fitting line (black) and 1:1 line (red dashed) for reference. The color gradient represents the distance to the 1:1 line, showing deviations between measured and derived values. (a) Validation of the SDD model, with an R² of 0.83, RMSE of 7.22 cm, and MAPE of 5.05%. (b) Validation of the TSM model, with an R² of 0.74, RMSE of 18.04 mg/L, and MAPE of 36.82%.