基于云雷达的大气0℃层亮带识别

Identification of Atmosphere 0 ℃ Isotherm Through Cloud Radar Data

为了研究8.6 mm云雷达探测大气0℃层亮带的能力,利用中国气象科学研究院灾害天气国家重点实验室的车载8.6 mm多普勒偏振云雷达(HMBQ)2008—2012年共计2 063次观测个例,分析云雷达在不同天气形势下的反射率因子、径向速度、线性退偏振因子在0℃层附近的变化特征,改进了一种通过云雷达探测产品反演大气0℃层高度的方法。研究表明:8.6 mm云雷达能够在无降水云、弱降水云、小雨、中雨甚至大雨的天气形势下,对大气0℃层进行观测,而且探测的0℃层亮带变化特征显著,能弥补常规天气雷达在夏季短时强对流、对流单体等小尺度天气预警业务中相关资料的不足。

In order to study the detection capability of 35 - GHz cloud radar about 0 ℃ layer bright band of the atmosphere, firstly based on the 2 063 cases data detected by the cloud radar - HMBQ of Chinese Academy of Meteoological Sciences in different places from 2008 to 2012, the variation characteristics of reflectivity factor, radial velocity and linear depolarization ratio of the cloud radar under different weather conditions were analyzed, and the method that could identify the 0 ℃ isotherm height derived from the detection products of the cloud radar was improved. Results show that the cloud radar - HMBQ could detect the 0℃ isotherm under different weather conditions such as no rainfall cloud, weak rainfall cloud, small rainfall, moderate rain and heavy rain, and the change feature of the 0℃ layer bright band detected by the cloud radar was remarkble, which could make up for the shortage of the relevant information in the early warning of small scale weather system in summer including shorttime strong convection, convective monomer and so on. The improved method compared to the original one, the accuracy and time resolution were raised, it could identify the spatial and temporal change of the 0 ~C layer bright band, and the results were in good agreement with radiosonde sounding 0℃ layer height.