一次雷暴前后大气折射率的多普勒天气雷达测量试验及结果

摘要

Dominated by atmospheric temperature,pressure and water vapor pressure,the atmospheric refractivity affects both the propagation path of radar EM-waves and the echo phase of an object.This implies that the variation of atmospheric refractivity can be retrieved by calculating changes of echo phase measured by Doppler weather radar.Thus the relevant water vapor information can be obtained for the research of local convection or advection.This paper explains the principle and method of refractivity retrieved from Doppler weather radar.The experiment results showed that the atmospheric refractivity retrieved from the S-band Doppler radar of Jiangsu Meteorological Observatory was reliable and effective in the case of a local thunder storm.The work can supply not only the remote-sensed data to the study on changes of water vapor and weather changes but also supporting data of water vapor field to numerical models,which is very promising in application.%由温度、气压和水汽压决定的大气折射率会影响天气雷达电磁波的传播路径和目标回波的相位。因此,通过测量目标回波相位的变化能够算出大气折射率的变化,进而得到水汽信息,为研究局地对流天气和水汽平流提供资料。本文阐述了多普勒天气雷达反演大气折射率的原理和方法,并利用江苏省气象台的S波段多普勒天气雷达反演了一次雷暴过程前后的大气折射率,表明了雷达探测大气折射率的可靠性。这项工作有望为研究水汽变化和天气过程提供高分辨率的遥感资料,也可以为数值模式提供水汽场辅助数据,有良好的应用前景。