云雷达反演层状云微物理参数及其与飞机观测数据的对比

Microphysical parameters retrieval by cloud radar and comparing with aircraft observation in stratiform cloud

首先根据滴谱假设分析了层状云降水回波强度、径向速度和速度谱宽与降水微物理参数的关系,检验了云雷达探测数据的可用性;然后在忽略空气上升速度和湍流对雷达观测的速度谱宽影响前提下,利用测云雷达观测的回波强度、粒子下落速度和速度谱宽数据进行了液态水含量和滴谱参数的反演试验,并与飞机观测的滴谱进行了对比分析。结果表明,8 mm雷达观测得到的3个量与雨滴谱分析得到的关系比较接近;层状云粒子尺度、数密度和含水量从云顶到云的回波强中心有明显的变化,粒子尺度的增加是回波强度增加的重要原因。毫米波雷达反演得到的降水微物理参数和飞机观测数据具有可比性。

The relationships among reflectivity, velocity and spectrum width of stratiform cloud are simula ted, and the availability of cloud radar data are analyzed. The reflectivity, velocity and spectrum width observed by cloud radar in vertical observation model are used to retrieve the liquid water content and the size distribution in stratiform cloud under the assumption of neglecting the air vertical speed and turbulence. The results show that the relationships among reflectivity, velocity and spectrum width observed by 8 mm cloud radar are similar to simulated values. The mean drop size, toll drop number and liquid water contend have obvious variations from cloud top to reflectivity center. The increase of reflectivity is due to the increase of drop size. The microphysical parameters retrieved by cloud radar have similar range with that by aircraft.