大气电场的FFT频谱分析及雷暴预报研究

采用傅里叶变换方法将时域数据转换到频域,针对首次地闪发生(简称“雷暴天气”)和首次地闪不会发生(简称“非雷暴天气”)的大气电场强度数据做了幅度谱分析.研究发现,首次地闪前0.5h的大气电场数据与非雷暴天气中任意时段0.5h的大气电场数据的幅度谱分布具有明显差异,两类天气的幅度谱分布有一定规律可循.在此基础上对样本整理分类,将两类天气的平均幅度谱视为判别标准,利用欧氏距离判别法,对63个未知天气样本进行判别分类和效果检验,结果表明,此方法可供短时临近的首次地闪预警工作中予以参考.

FFT analysis on atmospheric electric field and the applications in thunderstorm prediction

According to the atmospheric electric intensity data of the first happen CG flash(shortened as "thunderstorms") and the first unhappen CG flash(shortened as "un-thunderstorms"), the FFT(Fast Fourier Transform) method has been adopted to converse time data to frequency domain, which is used to analyze the amplitude spectrum of the data. The results show that there is an obvious spectrum amplitude distribution difference between the two sets of data, one of which belongs to 30 minutes before the first flash in thunderstorms and the other is related to arbitrary 30 minutes in un-thunderstorms. Furthermore, the two kinds of weather spectrum amplitude distribution may have followed some certain rules. Therefore, on the basis of sample classification, this paper regards two types of averaged weather spectrum amplitude as classification index; uses Euclidean distance method on 63 unknown weather samples to classify the data and examine the results, which shows that this new method can be considered as a reference for the approaching and short-term forecast of the first CG flash.