Retrieval of total suspended matters using field spectral data in Shitoukoumen Reservoir, Jilin Province, Northeast China

From August to October in 2006, three times of field spectral measurements with a Field Spec FR spectroradiometer (Analytical Spectral Devices, Inc., USA) were carried out in Shitoukoumen Reservoir, Jilin Province, Northeast China. Owing to the serious soil and water loss in the upstream, reflectance curves of the reservoir were characterized by high concentrations of total suspended matter (TSM). Extending the spectral analysis to 1200nm in the near-infrared band, this research revealed an obvious reflectance peak around 1070nm which was caused by the strong backscattering of high TSM. The method of partial least squares (PLS) regression was applied to retrieving the TSM. Reflectance in two spectral bands, i.e., 675-948nm and 1029-1105nm, were used as variables to develop PLS models. Traditional linear regression, first derivative model and logarithmic model were also used for the comparison of different models. Results showed that the PLS model based on Rrs(675)-Rrs(948) gave out best results with high precision and stability. Although the PLS model based on Rrs(1029)-Rrs(1105) did not have an outstanding performance due to lots of noise, the reflectance peak in the near-infrared band was an important TSM feature and its efficient exploitation would have a eunsiderable significance in TSM remote sensing.