摘要
针对雨滴谱的变化对降水估计的影响,提出根据激光雨滴谱仪上方雷达回波的结构特征将降水过程划分为对流云降水和层状云降水交替分布5个部分,通过基于2种降水类型的第Ⅰ种分类Z-R关系、基于5个部分的第Ⅱ种分类Z-R关系和基于整个降水过程的总体Z-R关系分析雨滴谱的变化对降水估计的影响。结果表明：当对流云降水向层状云降水过渡时,指数谱从无到有、多峰谱比例减小,Nw减小、μ增大、Dm变化不大;Nw与R变化相似,当Z增大时μ和Dm分别是递减和递增的;Z-R关系（Z=aRb）中a值变化范围较大、系数b在1~2波动且与层状云阶段相比,对流云阶段的a和b值较小;利用第Ⅱ种分类Z-R关系反演的雨强与基于雨滴谱仪观测数据计算的雨强最接近;雨滴谱仪在层状云阶段的反演效果明显强于对流云阶段,这与对流云降水中雨滴谱信息变化大且快等因素有关。
Specific to the influence of raindrop spectrum changes on precipitation estimation, indicating that the pre- cipitation process should be divided into five parts based on the features of raindrop size distribution, with convective cloud precipitation and stratiform cloud precipitation alternating, and analyzing different relationships between reflec- tivity and rainfall intensity including the classification based on two types of precipitation, five parts and the whole process respectively. The results show that when the type transits from convective precipitation to stratiform ones, exponential spectrum develops, the ratio of multi-peak spectrum decreases, the standardized parameter decreases, the shape factor increases while the average quality of weighting diameter shows little change; the standardized parameter has similar changes with precipitation intensity; When reflectivity increases, the shape factor decreases progressively while the average quality of weighting diameter shows exponential growth respectively; In the relationship of Z-R（Z = aRb） ,a＇s range is larger while b swings from 1 to 2; Compared with stratiforrn cloud precipitation, the coefficient a and b is smaller in convective ones; The inversion of rainfall intensity calculated by the second classified Z-R rela- tionship is closer to the actual ones; Disdrometer＇s inversion effects in stratiform ones is much better than convective cloud precipitation, which has something to do with the rapid change of raindrop spectrum in the stage of convective
出处
《成都信息工程学院学报》
2015年第1期88-95,共8页
Journal of Chengdu University of Information Technology
基金
国家重大基础研究973资助项目(2012CB441401)
国家自然基金资助项目(41175038)
关键词
大气物理与大气边界环境
雷达气象学
雨滴谱变化
分类Z-R关系
标准化Gamma分布
atmospheric physics and atmospheric boundary conditions
radar meteorology
raindrop spectral change
classified Z-R relationship
the standardized distribution of gamma DSD
