SPECTROMETRIC EXPERIMENTAL METHOD TO DETERMINE THE DISTRIBUTION OF SUSPENDED MATTER IN COASTAL ZONE OF HAI PHONG CITY USING STELLITE LANDSAT 7 IMAGES

Abstract

Hand-held spectrometer has been used in experimental research to build the deciphering keys of satellite images. However, it is difficult to measure the spectral reflectance in practice due to the continuous variation of solar radiation energy. This leads to the error in the analysis. This paper develops an experimental procedure to measure the spectral reflectance indoor to establish the correlation function between the spectral reflectance and the suspended matter concentration in seawater in Hai Phong coastal zone. This procedure eliminates the errors caused by the continuous variation of solar energy. The results reveal that the suspended matter concentration and the ratio NIR/GREEN have a direct proportion correlation with the following function: NTU = 3197 × (NIR/Green) – 511.37 with the correlation coefficient r = 0.979. The result from the Landsat 7 image taken on October 5, 2009, showed that the suspended matter content ranges from 244 NTU to 981 NTU, and spreads with decreasing concentration from the delta to the sea.