Fathoming The Attenuation Coefficient And Sediment Chroma Characteristics

Depth remote sensing refers to the premise of light to reach the bottom of the underwater topography by remote sensing technology to estimate. Light can reach the bottom depending on the degree of light attenuation in the water, while the diffuse attenuation coefficient (Kd) is that the degree of light attenuation in the water, so the depth of the attenuation coefficient is the basis of remote sensing. Shallow water depth in the optical remote sensing area, the bottom reflection on the inversion results will have a huge impact. Different regions of the characteristics of sediment will be some differences, which will cause the bottom of the reflected light intensity is different for the accuracy of remote sounding of water optical parameters inversion, inversion of optical parameters within the water will affect. This article based on spectral data, sediment data and sediment spectral color data were attenuation coefficient of water and sediment sensitive bands feature extraction.Based on the analysis of coastal water bodies and lake water characteristics of the attenuation coefficient and the measured spectral data and sediment color correlation we can draw the following conclusions: First, by analyzing the lakes and coastal water bodies at different depths the attenuation coefficient can be found, both 700nm and 800nm in the water near the two peaks, as the depth increases,800nm peak near or even disappear. Mainly because of the increase with depth, water absorption of light near the wavelength of 800nm decreased.Second, through analysis of different water bodies in the diffuse attenuation coefficient at 490nm and the relationship between remote sensing reflectance found that the lake water body kd (490) and the reflectivity at a wavelength of 555nm at the highest correlation. The coastal water bodies kd (490) and at a wavelength of 490nm,555nm and 670nm reflectance at the highest correlation.Third, through analysis of different water bodies at a wavelength of 490nm the attenuation coefficient and attenuation coefficient in the other bands can be found, No matter what body of water, at a wavelength of 490 nm spectral diffuse attenuation coefficient at the other bands at the linear attenuation coefficient, can be calculated by the formula (3-1) linear fit, the linear slope of the linear wavelength Relationship. Reflectance and red-green chroma a * showing a negative correlation, but less relevant, up less than -0.3; Reflectance and yellow-blue chroma b* showing a positive correlation, with the wavelength increases, the relevance decreases; reflectivity and brightness L in the entire wavelength range have shown a low correlation, the correlation coefficient of about-0.1. Show that the sediment color reflectance and b* yellow-blue chroma good correlation in the 500nm-700nm high; and brightness correlation between L-band in the whole range is very low.Forth, there is low correlation between reflectance and Red and green saturation a*; higher correlation with the yellow-blue chroma b*; the correlation with brightness L in the entire wavelength range have shown a low correlation. First derivative spectra reflects the slope of reflectance spectra, mass spectral data by analyzing the end of the first order derivative found in the spectrum She-yang Estuary point 500nm,655nm,850nm near the slope is relatively large; North aces in the 530nm and the spectral points Larger slope near 710nm; and snail Heng point spectrum in the vicinity of 530nm and 630nm greater slope. However, sediment color reflectance and b * yellow-blue chroma correlation in the 500nm-700nm high, because the wavelength of 600nm is mainly affected by the reflectivity after the water absorption and reflection of the impact of suspended sediment, suspended sediment to water and very sensitive to weaken Impact of substrate on the spectrum, so the quality of the end of the sensitive band selection 530nm.