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本文提出了一种从多普勒天气雷达单仰角径向速度图中的正-负速度区域对入手自动识别一类强对流天气的中层径向辐合的方法.首先,根据雷达探测机理,解释了由气流形成的辐合场一定会在径向速度图中形成局部最大正速度区域和局部最大负速度区域的特点,然后构建正-负速度区域对的识别算法,通过来自多个单仰角径向速度图的区域对配准和相关信息,判断雷达径向速度图中是否存在着中层径向辐合,推算辐合的强度、延伸厚度等重要参数,确定得到最优垂直剖面图的剖切方位.经对客观存在显著中层径向辐合的384例样本和不存在明显中层径向辐合的356例样本的测试,本文方法对显著中层径向辐合的识别率达到100%、误识率为0,与人工方法相比,本文方法把对中层径向辐合的识别时间从分钟级缩短到秒级,同时自动给出其强度、高度、厚度、位置等丰富的定量信息和恰当的可视化垂直剖面图.利用给出的参数信息进行了与强对流天气的相关性研究,验证了中层径向辐合与对流行地面大风的较强相关性,同时发现,最强中层径向辐合的高度对区分强冰雹与强降水、中层径向辐合的强度对估计冰雹尺寸具有良好的指示性.
This paper presents a method of automatically identifying the mid-level radial convergence of a class of strong convective weather from the positive-negative velocity region in the single-elevation radial velocity diagram of Doppler weather radar.Firstly, according to the radar detection mechanism, The convergence field formed by the airflow must form the local maximum positive velocity region and the local maximum negative velocity region in the radial velocity map. Then, the recognition algorithm of the positive-negative velocity region pair is constructed, To the registration and related information of the region of the velocity map, it is judged whether there exists radial radiation in the radial direction of the radar or not, and the important parameters such as convergence intensity and extension thickness are calculated to determine the optimal vertical profile Azimuth.According to the test of 384 samples that objectively exist significant middle radial convergence and 356 samples that do not have obvious middle radial convergence, the recognition rate of this method to the significant middle radial convergence is 100% Rate is 0. Compared with the artificial method, this method shortens the recognition time of the middle radial convergence from minute to second, and at the same time, it automatically gives abundant quantification of intensity, height, thickness and position Interest and appropriate visualization of the vertical profile.According to the correlation of the parameters with the strong convective weather, the correlation between the radial convergence in the middle layer and the prevailing winds on the ground is verified. It is also found that the strongest middle layer Radial convergence of the height of the distinction between strong hail and heavy rainfall, the middle of the radial convergence intensity of the hail size is estimated good indication.