The Mathematic Study On Multi-angle Polarization Information Of Suspended Sediment

The concentration of suspended sediments in water is one of important water qualityparameters. Suspended substance, especially the quantity of sand directly influences suchoptical nature as transparency, turbidity and water color of the water body, etc., influencesthe aquatic ecological condition and the movement course of the silt in river mouth littoralzone, too. So, it is very important to retrieve suspended sediment concentration in theresearch of water quality, ecology, environment, coast engineering, port construction, etc.The application of remote sensing technology makes it possible to get water image inlarge scale and quickly. And the images contain a great deal useful information onsuspended sediment. Through the processing and analysis of these images we can retrievesuspended sediment concentration distribution and dynamic change. Now it graduallybecomes a very important method to study suspended sediment. But, at present, theinformation that we use mainly concentrates on the electromagnetic intensity characteristicand geometry characteristic. Polarization information can be another dimension ofinformation source in remote sensing, hundreds of polarization images from American spaceshuttle proved this. Compared with no polarized measurements, polarized measurementscan provide more character information to distinguish objects;it is a kind of valuablepotential information. It can identify such different ground objects as aerosol, cloud, snow,water, etc. Especially for the surface with low contrast ratio to reflection radiant intensity,these polarization data can be utilized to detect goals effectively, and we can obtain valuableremote sensing message by polarization quantitative analysis on objects. Though some workon suspended sediments spectrum has been done, polarized reflectance characteristic ofsuspended sand has been done nothing at home, so the study on the polarizationcharacteristic of suspended sand is more significative.The study on the polarized spectral character is an important basis job of detectingsuspended sediments by polarization remote sensing. First, many research jobs on thissubject are introduced. Then the correlative theories of polarization and water-color remotesensing are addressed, including spectrum character, absorption and scattering coefficient ofpure water, as well as spectrum feature of suspended sediment. Third, polarimeter and themethod of polarization measurement of suspended sediments are described. Chap.4 involvesdata collection and processing. The spectrum character of suspended sediment is analyzedfrom some aspects, such as incidence angle, detective angle, azimuth, state of polarization,degree of polarization, etc. In addition, from the point of view of multi-angle polarizedremote sensing mechanism, the quantitative relation between polarized BRDF and BRDF ofsuspended sands has been studied. These studies provide a basis on analysis and abstractionof the characteristic parameters of the silt by polarization remote sensing.