基于数字摄像能见度仪的北京地区降雨和雾霾天气能见度对比分析

数字摄像能见度仪（Digital Photographic Visibility System，DPVS）仿照人工目测能见度的原理测量大气能见度。本文应用2017年3—8月北京地区DPVS、前向散射仪（PWD22）、大气透射仪（LT31）三种观测仪器在降雨天气和雾霾天气观测数据进行了对比。结果表明：能见度观测数据与相对湿度、颗粒物浓度、降水粒子等要素之间有明显的负相关性；在低能见度天气条件下，三种仪器观测数据变化趋势一致，但存在一定的差异；DPVS在中雨天气、大雨天气、暴雨天气和中度雾霾天气中，观测数据离散性更小，稳定性更好。但DPVS在白天和夜间的交替过渡期观测值不够稳定，这也是今后算法优化的重点方向。

Comparison of visibility in rainfall and haze-fog weather in Beijing using digital photographic visibility system

Digital Photographic Visibility System(DPVS)is an instrument to measure atmospheric visibility based on a similar principle of artificial visual measurement.The observed visibility from the DPVS,a forward-scattered meter(PWD22),and an atmospheric transmissometer(LT31)under rainfall and haze-fog weather events were compared in Beijing from March to August of 2017.The results indicated that visibility has an obvious negative correlation with relative humidity,particle matter concentration,and precipitation particles.Under low visibility conditions,the variations of visibility observed from three instruments are basically consistent with each other in spite of small differences.Visibility observed from the DPVS has smaller discreteness and better stability under moderate rainfall,heavy rainfall,rainstorm,and moderate haze-fog events.However,the visibility observed from the DPVS has large uncertainty during the transition period between daytime and nighttime,which should be improved by optimizing the algorithm in the future.