傅立叶相位分析导风技术中的频谱分析

ANALYSIS ON FREQUENCY OVERLAP IN FOURIER ANALYSIS TECHNIQUE

本文介绍了应用于傅立叶相位分析导风技术中的DFT变换理论,并模拟分析DFT计算中的频谱分离和混叠两种现象及其对导风的影响。结论认为,傅立叶导风技术不需要计算所有谐波的相位,只要计算分离区或混叠区之前的低次谐波的相位,这些低次谐波的相位速度与真实速度一致,且与谐波振幅和初相位的取值无关,可用于风速计算。

The theory of Fourier technique on GOES high temporal resolution images is based on Fourier analysis of continuous function（Fourier progression）. Because the satellite cloud image is made of scattered pixels, Discrete Fourier Transforrh（DFT） must be used in practical computation. This article introduces the DFT theory used in the Fourier analysis technique in tracking cloud motion and analyzes the frequency overlap phenomena and the frequency discretion phenomena in DFT computation by mathematical simulation.