【作者】 程晓丽；

【导师】 王萍；

【作者基本信息】 天津大学 ， 模式识别与智能系统， 2008， 硕士

【摘要】 天气雷达是探测降水系统的主要手段,是对强对流天气(冰雹、大风、龙卷和暴洪)进行监测和预警的主要工具。为了以图像的形式从各个视角直观展现雷达基数据文件所蕴含的信息,以辅助气象预报和研究工作,本文主要做了以下几方面的研究和探索。1.构建并显示雷达反射率图像和径向速度图像我国新一代天气雷达的优点之一是基数据为数字化的,经过算法的处理可以形成一系列的产品。本文依据雷达基数据产品文件结构,从中读取数据信息并生成反射率图像和径向速度图像。经测试,一组18张图像的总体生成时间小于3秒,图像质量及真实率达到已有产品的水平。2.实现基于多锥面数据的任意三维剖面为了使云体的立体结构和回波强度分布可视化,本文汇集各仰角即多锥面的数据信息研究云体的三维剖面图像的生成方法。与已有的剖面图不同的是,本文将剖面置于三维坐标系中,使其携带有丰富的空间位置信息;同时因剖面截线的长度和方位不受任何限制,又使其具有了很强的灵活性。3.基于三维剖面的云体结构可视化方法在实现了一个位置上的静止剖面图之后,令剖面的截线沿径向平行移动,随之形成一个剖面系列组,再根据气象工作者的专业知识和经验,确定最佳的截线角度;根据视觉特点,确定最佳的观测角度,从而实现了对所剖云体在最佳剖面角度和最佳观测视角下的云体构成的展现。4.分析并提取云体三维构成特征云体在三维构成上有很多特征有待研究、归纳和自动提取,及时恰当地将它们提取出来,将有助于定量地描述云体的三维结构,有助于对天气状况的分析和理解,有助于提高预警预报强对流天气的准确率。本文对此项工作做了初步尝试,定义并提取了反映云体三维构成的能量、厚度、高度及其变化特征。本文工作均在Visual C++ 6.0软件开发平台下实现,实验测试结果达到预期目标。更多还原

【Abstract】 The pulse-Doppler radar is widely used in weather investigation, is the main instrument that can detect precipitation system and monitor Severe Convective Weather (including hailstorm, gale, cyclone, violent flood and so on).In order to exhibit information contained in radar initial data files from various angles of view by means of bitmaps, this dissertation study the following aspects. The productions will be used to assist meteorologic analysis.1. Build and display the reflectivity images and velocity images of Doppler radar.One merit of Chinese new generation of weather radar is that the initial data is digital, so the initial data can be processed by appropriate algorithms to create a series of productions. According to the framework of radar data file, this system read reflectivity data and velocity data information from it. Then designed algorithms to build a reflectivity image or a velocity image. The system built eighteen radia bitmaps in less than three seconds, and the image quality is satisfying.2. Realize three-dimensional section plane of discretionary transversal using radar data in multiple elevationsIn order to visualize the three-dimensional conformation of cloud and echo distributing status, this system synthesized every elevation’s data information to realize cloud three-dimensional section plane. Compared with conventional weather section, this section is in a three-dimensional reference frame, so it has spacial position information. Also, in this system, the transversal’s angle and longness can be discretionary.3. The cloud conformation’s visualization technique based on three-dimensional section planeWhen the transversal moves along a radius, both spacial position and content of the section change. This evolvement course is represented through a sequence of section planes. Though the transversal can be discretionary choose an appropriate transversal according to aerography knowledge and experience can get a better observational effect. Further more the system selects an appropriate observing angle according to optic factors to exhibit the cloud conformation as clear as possible.4. Analyze and pick up cloud three-dimensional conformation charactersThere’re a lot of characters in cloud three-dimensional conformation to be studied, induced and picked up automatically. Define appropriate characters and pick up them in time can help to describe cloud three-dimensional conformation quantificationally to analyze and understand the weather status and to improve the veracity of severe convective weather forecast. Primary attempt has been made in this dissertation, some characters about cloud three-dimensional conformation have been defined and picked up. They are energy, thickness, height and their changes.All the software developments are realized in the Visual C++6.0 platform. In this dissertation, report algorithms’effect by means of bitmaps, and the processing results are satisfying.更多还原