【摘要】 在雷达回波反射率图中,预示冰雹天气过程的云体具有视觉特征,它们一般由云体核、以核为中心的主体、主体外侧的过渡带及云砧构成,并且具有核的强度高、主体呈钩状、过渡带较窄等明显特征,这些特征在冰雹形成的前期具有一定的规律性.为将它们客观地提取出来,对其展开模式分析,提出一种探针模型,构建出基于探针模型的反映雹云过渡带特点的梯度特征和反映钩状主体的多个形态特征.经测试,超过92%的样本在用探针提取的冰雹单体的梯度特征和形状特征上呈现出良好的区分度,并验证了这些特征的有效性.更多还原

【Abstract】 In radar reflectivity images,the cloud associated with hail shooting process consists of four partst:he core,the body with the core being the center,the transition band outside the body,and the tail part.Moreover,hail clouds have some visual features that the reflectivity of the core is strong,the body is hook-like,and the transition band is thin.All these features are indicative in earlier stage of the hail′s development.In order to extract these features impersonally,a model called probe was constructed.And based on the model,a method for feature extraction,including the gradient information of the transition band and the morphological character of hook-like body,was proposed for hail auto-forecasting.Testing results show that favorable separability was shown between hail and non-hail cells at gradient and shape features extracted by probe with over 92% samples.And then the effectiveness of these features was verified by experiments.更多还原