Spatial distribution characteristics of surface sediment grain-size parameters on the intertidal flat using hyperspectral remote sensing data

Among totally 242 spectral bands ranging from 400 to 2 500 nm of Hyperion hyperspectral remote sensing data,it was found that two bands with reflect ance of 1 215 and 2 133 nm had relatively good correlation with the sediment grain-size parameters of mean diameter,skew ness,medium diameter and sorting coefficient.And further more,the combination of the sum of these two bands divided by their difference had a significant linear correlation with the mean diameter,skew ness and medium diameter while the sorting coefficient had a notable linear relationship with the discr epancy of the mean diameter and medium diameter.On the basis of these relation ships,four linear regression models were established and applied to getting the spatial distribution characteristics of grain-size parameters at the southern part of intertidalflat near the Sheyang Estuary in Jiangsu Province,China.Verification by independent samples show that the mean relative precision and the mean absolute precision exceed 75.70%and 72.17%,respectively. The spatial distribution pattern of grain-sizes indicates that in the direction from north to south that parallel to the coastal line,the grain-size diameters become finer,the sorting charact eristics become worse and the distribution of skew ness moves from near symmetry to positive deviation.While at the direction from land phase to sea that perpendicular to the coastal line,the grain-size diameters change coarser,the sorting character istics become better and the distribution of the skew ness moves from positive to near symmetry. But near the medium tidal level area,sediment is the mixture of fine and coarse matter and the mean diameter is a litter larger than near by part.sorting charact eristic becomes worse from medium to either land or sea direction.These variation trends are in accordance with hydrodynamic enviro nments and sources of sediments well.