Experimental Analysis Of Zenith Region Skylight Polarization Pattern

During the process of atmospheric transmission of the sunlight, plenty ofpolarized light is produced by light-scattering caused by various components in theatmosphere, as well as reflection caused by non-metal surfaces, such as cloudlayers and earth’s surface. There are many different properties of polarized light inthe atmosphere forming the particular skylight polarization pattern which containsrich spatial orientation and atmospheric parameters information. The skylightpolarization pattern is mainly determined by the location of the sun, the distributionof various components in the atmosphere, climatic conditions, properties of theearth’s surface and underlying surface. The information of skylight polarization hasa wide range of application in many areas, such as the analysis of atmosphericoptical properties, polarized remote sensing, perceptual mechanism in biologicalpolarization and the study of bionic polarization navigation robot etc. Taking thepolarization characteristic of transmitting sunlight in the atmosphere as thetheoretical basis, on the viewpoint of acquisition method and implementationtechnique of atmospheric polarization information, this thesis mainly focuses onthe study of acquisition technique and experimental analysis of zenith regionskylight polarization pattern with a self-built imaging polarimeter in Hefei and itssurroundings. This thesis illustrates the distribution and changing rules in differenttime and places of zenith region atmospheric polarization characteristics when it isin typical weather, typical earth’s surface and different spectrum, which canprovide a basic experimental support and validation for bionic polarized lightnavigation, polarization detection and some other applied researches.The main work of this thesis is as follows:(1) Research history, research status at home and abroad as well ascorresponding research results of the scattering skylight polarization characteristicsare summed up. It analyzes the polarization characteristics of light. Based on themechanism of atmospheric scattering, the formation and characterization methodsof skylight polarization pattern are elaborated, besides, the simulation of Rayleighscattering model is also achieved. (2) According to the experimental demand of detection about zenith regionpolarization characteristics, an imaging polarimeter for local sky area isconstructed on the viewpoint of effective acquisition of atmospheric polarizationinformation. The set-up and corresponding calibration as well as testing are made,and the results show that the detecting system is stable and reliable.(3) A large number of outdoor detecting experiments of zenith region skylightpolarization pattern are carried out with the imaging polarimeter. The distributionand changing rules in different time and places of zenith region atmosphericpolarization characteristics when it is in typical weather, typical earth’s surface anddifferent spectrum are studied. And influences of different natural factors on zenithregion skylight polarization pattern are analyzed. Also, the consistency anddifferences of measured and theoretical models are compared. Large number ofexperimental analysis shows that: the distribution of zenith region skylightpolarization pattern has a good symmetry. There’s a much greater change in degreeof polarization than angle of polarization influenced by different factors, that is,angle of polarization has a high robustness.