在对云微物理的研究中,雨滴谱是一个重要参量,对理解云内成雨机制的探索、人工增雨效果的检验等方面都具有重要意义。利用2016年4-5月广东龙门的个例,讨论Ka波段毫米波雷达和C波段调频连续波雷达探测能力的差异,对比它们在不同云个例中雨滴谱的反演情况,得到如下结论:由于C波段雷达的波束宽度比Ka波段雷达大很多,故在小粒径区的探测上,其粒子数浓度略大,但最终对雨滴谱分布的拟合影响较小。探测层状云时,两部雷达对雨滴谱的反演效果基本一致;探测积层混合云及积雨云时,Ka波段雷达反演的雨滴谱数浓度从粒径约为1.2 mm处开始小于C波段雷达。米散射和衰减对雷达反演雨滴谱的影响本质上是作用在功率谱密度上,导致大粒径雨滴谱反演的偏低及回波强度的偏低,故在雷达回波订正上可以考虑从功率谱密度入手进行订正。
In the study of micro cloud-physics, drop size distribution (DSD) is an important parameter, it has meaningful to understand the start mechanism in cloud, the inspection of artificial precipitation and so on. The paper used the cases in Guangdong Longmen in April and May 2016, discussed the differences of detection ability Ka-band millimeter radar and C-band frequency modulated continuous wave radar, compared the retrieval condition in different cases. The result is as follows : cause the beam width of C-band radar is larger than Ka-band radar, the particle number concentration of C-band is larger than Ka-band in small diameter area. But it has less influence on the DSD fitting. In the detection of stratiform cloud, the retrieval of DSD by two radars is basically the same. In the detection of cumulus mix cloud and convective cloud, the particle number concentration of Ka-band radar is less than C-band radar started at the diameter of 1.2 mm. In fact, the power spectrum density is effected by Mie scattering and attenuation, it lead to the decrease of particle number concentration in larger diameter and the decrease of echo intensity, so it maybe useful to make echo cor- rections in power spectrum density.