The Research On The Near-infrared Light Transmission Characteristics And Polarization Distribution In The Clouds

The transmission process of the light in the clouds will occur scattering, reflection, andabsorption with the cloud droplets. This process will bring to pass two physical changes inthe clouds. On the one hand, after the incident light scattering multiple times with the clouddroplets, the polarization information carried by the light will changed. The final result ofthe polarization information received from the detector will be the interaction between theoriginal polarization information from the sunlight and the clouds. On the other hand, theclouds have a strong effect that can strongly absorb and scatter the sunlight. It can deflectmost of the incident visible light to the outer space and also can absorb a great mount ofinfrared light energy. This will reduce the radiation energy of the sunlight reach to theearth’s surface. In this paper, we study the characteristic of the incident light transmitted inthe clouds at the near-infrared bands and the different degree of polarization, thepolarization distribution in the clouds, the influence of the clouds on the incident light atnear-infrared bands.(1) The theory of the atmospheric radiative transmission is studied. The scatteredcharacteristic of the clouds particles at different clouds types is analysed. Based on thisanalysis, transmission model of the different particles in the clouds is established. And withthe help of the particles microscopic composite characteristics, the clouds are divided intotwo types, water clouds and ice clouds. This provides a theoretical basis of the transmissionmodeling of the cloud.(2) The influence factors of the transmission characteristic in the cloud is investigated.Based on the fixed clouds type, the incident light wavelength and the polarization degreeare the main factors that influence the polarization information of the light. The incidentlight wavelength is also t the main factor that affect the attenuation of light wave in theclouds.(3) The transmission process of the light wave in the different clouds type models aresimulated by using Monte-Carlo method. Based on the actual characteristics of clouds, theMonte-Carlo method is optimized and set the relevant parameters in the simulation program.The characteristics of the transmission are obtained in the clouds at the near-infrared bandand this provides a theoretical basis of the transmission characteristics of clouds.(4) Based on the simulation model. The factors that influence the transmission characteristics of clouds are investigated. Fixed the clouds parameters, setting differentwavelengths and the different degree of polarization of incident light, the influence of theincident wavelength and degree of polarization on the polarization transmission in theclouds is investigated. The polarization distribution of the outgoing light on the detector isanalysed. Different wavelengths of the incident light are set to study the attenuation of theclouds.