A Study Of Sea Fog Characteristics Based On SNSPD Lidar System

SNSPD is a new single photon detector.SNSPD has the advantages of high efficiency,low dark count,high detection speed,wide response spectrum and so on.SNSPD has great potential in quantum communication,integrated circuit detection,laser ranging,weather detection and prediction and other fields.Sea fog is a common phenomenon of sea weather,which has a significant impact on fishery,navigation and flight safety.Laser weather radar is a commonly used sea fog detection technology,with excellent azimuth accuracy,distance resolution and high quality of significantly reducing background noise.Laser photon radar based on single photon detector is mainly used to detect cloud range and concentration,humidity,wind field,air pollution,pollutant diffusion and weather forecastIn this paper,the sea fog concentration and distribution in the 90 km diameter area are measured by SNSPD lidar system.First,SNSPD is applied to the Mie scattering weather prediction lidar system to test and verify the reliability of the system by the benchmark of a known island distance measurement.The fog echo signal distribution in the range of 42.3 km～63.5 km and 53.2 km～74.2 km is detected by the system.According to the atmospheric fog concentration formula,the fog concentration at the distance of 45 km and 55 km are 103 cm-3 and 303cm-3 respectively at different time.The velocity of fog movement in the direction of laser emission is 13 km/h,which is consistent with the weather and proves the SNSPD’s ability to detect long distance meteorological phenomenon.can extend its detection capability to the theoretical limit for sea fog measurements.In order to further measuring the fog concentration distribution and verify the feasibility and accuracy of the SNSPD lidar applied to meteorological measurement and prediction with the limitation of the lidar system’s repeating frequency,the echo signal is measured in the other direction from 31.6 km to 42.0 km.In the range of 36.6 km～37.8 km,the maximum fog concentration is 265 cm-3,the fog concentration is dense in the middle and small in the two edges.The measured data in this paper is compared against the results from Xu Jingqi and others which "Multiple-use drop spectrometer" was used to measure the fog concentration in Maidao close to Qingdao and it’s found that the fog concentration change region matches.