A study on the Influence of Surface Waves in the Investigation of Turbidity using Visible and Near Infrared Remotely Sensed Satellite Data

Abstract

The satellite remote sensing is prevailing in sea areas monitoring for environmental conservation since the visible and near infrared bands of satellite data are sensitive to turbidity and chlorophyll. In previous studies on this subject, however, the effect of the surface waves on the brightness values has never been considered so far. If the brightness values of the visible and near infrared bands are greatly enhanced by the surface waves, its effect should be detected and eliminated from the apparent values not to make confusion.
The authors have examined the MOS-1 MESSR data containing the areas with probable effect of the surface waves, which are extended widely enough to classify, and proposed a definition of the surface waves factor using the statistics on the brightness values.
We carried out the unsupervised classification by Histogram Overlay Method (HOM) on the basis of this definition and compared with the results by conventional cluster analysis. The areas with effect of the surface waves were discriminated from the turbid areas only when the HOM was applied. In addition, its effect was more pronounced in the near infrared band.
The effect of the surface waves on the reflection intensity of the sun light was investigated experimentally and theoretically. It was shown that the strongest reflection intensity is observed by satellites in summer when the incident angle of the sun light becomes the highest and when the direction of the wind is south-southeast, i.e., the same direction with the sun light.