Correlations between water quality indexes and mid-infrared spectra in river network areas of Suzhou city

Fifty typical stations were selected to measure mid-infrared spectroscopy in the river network areas of Suzhou city, on November 23, 2009 and five water quality parameters were analyzed for every measured station, including Total Phosphorous (TP), Total Nitrogen (TN), K, Mg and Cu. The correlations between the water quality indexes and spectral reflectance were analyzed, and the linear models were built based on single band and ratios. Significantly positive correlation was found between the spectral reflectance ratios and TN. At the same time, negative logarithmic correlation was also found between the spectra reflectance and TP concentration. The two models had the good correlation coefficient of more than 0.74 between the water quality parameters and the spectra reflectance. The study indicated that the water quality indexes can be monitored by mid-infrared spectroscopy technology, which would provide the water supply and conservancy authorities with referenced spatial information to manage water resources.