基于修正VAD技术的非线性风场反演方法研究

Research on Nonlinear Wind Field Retrieval Method Based on Modified VAD Analysis

  • 摘要: 对流风暴的新生和发展演变与三维风场存在密切联系,多普勒天气雷达可利用多普勒效应测量径向速度,可及时地反映风场信息。基于线性风场假设和全方位均匀采样的速度方位显示(VAD)技术是目前应用最广泛的使用单部多普勒雷达反演风场的方法,然而对于台风、龙卷等强对流天气系统,其内部风场空间分布复杂,线性风场假设不成立,以及由于机动平台非理想运动无法保证等方位间隔的均匀采样,导致反演精度不高。本文提出了一种基于修正VAD技术的非线性风场反演方法,建立了机动平台下视圆锥扫描几何模型以及复杂风场的非线性空间分布模型,相对于传统VAD技术,该方法更能反映真实的复杂风场结构,具有更好的反演效果。

     

    Abstract: The birth and development of convective storms were closely related to the three-dimensional (3D) wind field. The Doppler weather radar could use the Doppler effect to measure the radial velocity and reflect the wind field information in time. The velocity azimuth display (VAD) technology based on linear wind field assumptions and omni-directional uniform sampling was the most widely used method to retrieve three-dimensional wind fields for single Doppler radar. However, for strong convective weather systems such as typhoons and tornadoes, the spatial distribution of the internal wind field was complicated so that the assumption of linear wind field was not valid and the uniform sampling at equal azimuth intervals cannot be guaranteed due to the nonideal motion of the mobile platform, which resulted in low retrieval accuracy. This paper proposed a three-dimensional wind field inversion method based on the non-uniform sampling modified VAD technology. The nonlinear spatial distribution model of the complex wind field and the omnidirectional non-uniform sampling data model of radial Doppler velocity were established. Compared with the traditional VAD technology, the wind field retrieval results of this method can better represent the real complex wind field structure and better retrieval effects.

     

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