부산대학교 도서관

In this study, only the first return stroke of CGs and NBPs lightning waveform are thoroughly analyzed using two different methods in wavelet and temporal. 4 parameters which are the pulse duration (PD), rise time (RT), zero-crossing time (ZCT) and full width half maximum (FWHM) for temporal analysis meanwhile the frequency and power spectrum are the parameters analyzed for wavelet analysis respectively. Comparison according to criteria were included as well as to differentiate lightning properties. 50 data from negative cloud to ground (NCG), narrow negative bipolar pulse (NNBP) and narrow positive bipolar pulse (NPBP) were used in wavelet transform along with 40 data from positive cloud to ground (PCG). The result of the wavelet has shown that narrow bipolar pulses (NBPs) radiate energy at a higher frequency than any other cloud to ground (CGs) lightning. However, CGs has 4 times higher peak power spectrum than NBPs. In temporal analysis, 100 data from NCG, NNBP and NPBP have been analyzed accordingly, while PCG has only 40 data available to be analyzed. From the time domain characteristics, in most of the above-mentioned parameters the NBPs have much smaller value compared to the CGs. [ABSTRACT FROM AUTHOR]