Understanding the Variability of Z-R Relationships Caused by Natural Variations in Raindrop Size Distributions (DSD): Implication of Drop Size and Number
Understanding the Variability of Z-R Relationships Caused by Natural Variations in Raindrop Size Distributions (DSD): Implication of Drop Size and Number
复制标题
了解雨滴尺寸分布 (DSD) 自然变化引起的 Z-R 关系的变化：雨滴尺寸和数量的含义
DOI：
10.4236/acs.2011.13017
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发表时间：
2011
影响因子：
0.6
通讯作者：
Manlandon Koffi
中科院分区：
文献类型：
--
作者：
A. D. Ochou;E. Zahiri;B. Bamba;Manlandon Koffi
在利用雷达反射率Z与降雨率R（Z-R）之间的必然关系进行雷达降水估测的问题上，主要的局限性在于这种关系的可变性。事实上，先前的几项研究已经表明，这种关系在空间和时间上存在很大的变化，从一次降雨事件到另一次降雨事件，甚至在一次降雨事件内。最近的研究表明，雨滴大小分布的变化以及Z-R关系更多地是降雨系统内复杂的动力学、热力学和微物理过程的结果，而不是地面降雨信号的对流/层状分类的结果。地面雨滴数和雨滴大小是上述各种过程的结果，分析它们的变异性与Z-R关系的关系是一个合适的途径。在这项研究中，我们调查了在许多研究中使用的总雨滴浓度数NT和中位体积di-d 0，并表明，这两个“观察到的”参数的组合似乎是一个有趣的方法，以更好地了解降雨事件中的Z-R关系的变化，而无需假设一定的分析雨滴大小分布模型（指数，伽玛，或对数正态）。本研究是基于在非洲不同季节和地点收集的disdrometer数据的分析，旨在显示雨滴大小和数量的影响程度方面的Z-R关系的变化。
In the issue of rainfall estimation by radar through the necessary relationship between radar reflectivity Z and rain rate R (Z-R), the main limitation is attributed to the variability of this relationship. Indeed, several pre-vious studies have shown the great variability of this relationship in space and time, from a rainfall event to another and even within a single rainfall event. Recent studies have shown that the variability of raindrop size distributions and thereby Z-R relationships is therefore, more the result of complex dynamic, thermody-namic and microphysical processes within rainfall systems than a convective/stratiform classification of the ground rainfall signature. The raindrop number and size at ground being the resultant of various processes mentioned above, a suitable approach would be to analyze their variability in relation to that of Z-R relation-ship. In this study, we investigated the total raindrop concentration number NT and the median volume di-ameter D0 used in numerous studies, and have shown that the combination of these two ‘observed’ parame-ters appears to be an interesting approach to better understand the variability of the Z-R relationships in the rainfall events, without assuming a certain analytical raindrop size distribution model (exponential, gamma, or log-normal). The present study is based on the analysis of disdrometer data collected at different seasons and places in Africa, and aims to show the degree of the raindrop size and number implication in regard to the Z-R relationships variability.