Spectral parameters estimation in precipitation for 50-MHz band atmospheric radars
Spectral parameters estimation in precipitation for 50-MHz band atmospheric radars
复制标题
50 MHz 频段大气雷达降水频谱参数估计
DOI：
10.1002/2014rs005643
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
and Mamoru Yamamoto
中科院分区：
文献类型：
--
作者：
Tong Gan;Masayuki K. Yamamoto;Hiroyuki Hashiguchi;Hajime Okamoto;and Mamoru Yamamoto
50兆赫波段大气雷达可以同时探测晴空回波和水凝回波。然而，为了计算光谱参数（即，回波功率、多普勒速度和谱宽），必须将晴空回波与水凝物回波很好地分离。在这项研究中，我们提出了方法（顶部方法和两个回波方法）计算光谱参数的降水区。当存在雨滴或回波强度较小的固体水凝物时，使用顶部方法。top方法通过使用晴空回波的峰值强度来设置回波截止电平。回波截止电平用于从水凝回波中分离出晴空回波。当存在回波强度较大的固体水凝物时，采用双回波法。双回波法利用晴空回波和水凝物回波之间回波强度的局部最小值来设置回波截止电平。在2009年10月26日的一次降水过程中，中高层大气雷达的垂直波束获得的测量结果被用于评价顶部回波法和双回波法的性能。通过数值模拟确定了顶回波法和双回波法的回波截止电平。测量结果表明，顶回波法和双回波法对减小光谱参数的误差是有效的。
Fifty megahertz band atmospheric radars (ARs) can detect clear air echoes and hydrometeor echoes simultaneously. However, in order to calculate spectral parameters (i.e., echo power, Doppler velocity, and spectrum width) of the clear air echo accurately, the clear air echo must be separated from the hydrometeor echo well. In this study, we propose methods (top method and two-echo method) for calculating the spectral parameters in precipitation region. The top method is used when raindrops or solid hydrometeors with small echo intensities exist. The top method sets an echo cut level by using the peak intensity of the clear air echo. The echo cut level is used for separating clear air echoes from hydrometeor echoes. The two-echo method is used when solid hydrometeors with large echo intensities exist. The two-echo method sets the echo cut level by using the local minimum of echo intensity between the clear air echo and the hydrometeor echo. Measurement results obtained by the vertical beam of the middle and upper atmosphere radar during a precipitation event on 26 October 2009 were used for evaluating the performance of the top and two-echo methods. The echo cut levels of the top and two-echo methods were determined from numerical simulation. The measurement results demonstrate that the top and two-echo methods are useful for reducing errors of spectral parameters.