Study Of Suspended Sediment Spectral Characteristics And The Concentration Of Remote Sensing Mode

Remote sensing has proved to be a useful method in measuring suspended sediments concentration (SSC). The key to the success of remote sensing in such a role is the strong positive relationship that exists between SSC and remote sensing reflectance(R). This paper takes tidal creek out of the New Beiling Gate in Haian County Jiangsu Province as study area, measuring spectral radiance of suspended sediments water and collecting surface layer suspended sediments data simultaneously. Laboratory based studies related to R response of suspensions carrying three different particle sizes, and concentration using suspended sediments in situ, based on which the author chooses optimal wavelengths for the estimation of SSC and reveals the quantitative relationship between R and SSC for a given size. Quantitative remote sensing models for the prediction of SSC have been evolved with due involvement of the median diameter (D₅0) of sediment. This study has educed the following findings and conclusions:1.The characteristics of reflected spectrum of suspended sediment and the relationship between R and SSC improve the precision of measuring water depth in remote sensing method.2.The author adopts the method put forward by NASA in water spectrum measurement, examining out the radiance of water, sky scattered light and standard reflecting board and calculating the R. The first time fiber spectrometer is used in suspended sediment water reflectance measurement. Through comparing results from two spectrometers, the reflectance measured under the water using fiber spectrometer is similar to the actual reflectance calculated from the data measured by the FieldSpec handheld spectrometer.3. Reflectance of all wavelengths for any size increases with SSC rising, but has different increasing extents. The reflectance cure of suspended sediment water has two peaks. Reflectance also increases with a decrease in particle sizes in the same SSC. According to the analysis about the reflectance characteristics of suspended sediment water and the correlation coefficient between R and SSC, bands from 730⁷50nm, 800⁸20nm and 900⁹30nm were selected as the optimal wavelengths for the estimation of SSC.4. Quantitative models between R and SSC for a given size (D₅0=0.032nm) are set up based on the data measured in laboratory experiments. Quantitative remote sensing models for the prediction of SSC have been evolved with due involvement D₅0 of sediment using the data acquired in Haian County. The predictive and observed values of SSC by various models are evaluated, in which principle component model shows better precision.