Spectral correlation analysis of chlorophyll-a concentration for inland water

摘要

Remote sensing technology shows huge potential in the fields of monitoring the quality of water. Concentration analysis on phytoplankton chlorophyll-a in inland water has become a research hotspot in remote sensing. The purpose of this paper is to calculate correlation between the chlorophyll-a concentration and reflectance data acquired from the terrain spectrometer. The same comparison is done on the concentration of turbidity. The spectral data is captured from four different location of Zhuolu county in Hebei Province through a terrain spectrometer ranging from 351nm to 960nm. The 1 nm spectral resolution provides the capability to estimate the maximum sensitivity spectral data of the chlorophyll-a and turbidity concentration. Besides comparing each singe band with the concentration of chlorophyll-a and turbidity, the combinations of two different spectrums are also analyzed to acquire the maximum sensitivity. The correlation between single band reflection and chlorophyll-a concentration is serious impacted by concentration of turbidity. Meanwhile the difference, ratio and sum-difference combination of two spectrum band combination has shown different response when compared with chlorophyll-a and turbidity. The band combination algorithm can abstract the chlorophyll-a concentration from turbidity. It is proved that high correlation coefficient can be found in specific wavelength regions through the difference reflection between (698~701nm) and (673~684nm), the ratio reflection between (662~681nm) and (532~588nm), and the sum-difference reflection between (662~677nm) and (559~588nm).