环境风对光学雨滴谱仪探测的影响

Effect of Environment Wind on Measurement of Optical Disdrometer

为了研究环境风影响下激光雨滴谱仪探测数据的应用,基于北京2018年6—8月的多次降水过程,对比架设于不同高度的OTT-Parsivel激光雨滴谱仪和超声风温仪的探测结果,分析环境中不同强度的水平和垂直风对雨滴谱仪观测的影响。结果表明,水平风速小于10 m/s且垂直风速大于0.4 m/s时,利用OTT-Parsivel观测的速度谱估计垂直风速,80%以上的估计值与超声风温仪观测值一致;对雨滴垂直速度的修正会使计算得出的直径1 mm左右的雨滴数浓度发生显著变化,进而影响雨滴谱衍生物理量;借助定义的样本速度谱平均标准差和异常雨滴比例两个特征参数,可以识别80%水平风速大于10 m/s的样本。

To analyze the data detected by optical disdrometer under the influence of environment wind,this paper uses data measured by OTT-Parsivel and ultrasonic anemometer during several precipitation processed in 2018 in Beijing,and studies how horizontal and vertical wind affect the measurement of disdrometer respectively.When horizontal wind speed is less than 10 m/s and vertical wind speed is less than 0.4 m/s,more than 80%vertical wind speed estimated by velocity of hydrometeors from OTT-Parsivel are consistent with that given by anemometer.While the correction of velocity of hydrometeors brings significant change to raindrop whose diameter is about 1 mm,thereby affects other parameters.Moreover,this paper defines two feature parameters calculated from size and velocity of hydrometeors:the average of standard deviation and the ratio of outlier,which can distinguish more than 80%samples with horizontal wind speed more than 10 m/s.