【作者】 李颖；

【导师】 王振会；

【作者基本信息】 南京信息工程大学 ， 雷电科学与技术， 2012， 硕士

【摘要】 电场的活动与太阳活动、雷电活动、沙暴和地震等息息相关,是空间物理、大气物理和空间环境等领域重要的特征参数。研究电场资料在不同天气条件下的时频特征有助于我们分析天气过程,也为我们预报首次地闪打下基础。本研究主要使用公益性行业科研专项“基于遥感的雷暴云大气电场强度分布预测研究”项目组获取的大气电场仪资料,并以江苏省闪电定位仪资料和南京多普勒雷达资料作为辅助,分别讨论和分析了不同天气条件下地面大气电场的时间变化特征和频域变化特征,主要得到以下结论：(1)晴空条件下大气电场的日变化主要分为单峰单谷和双峰双谷两种变化波形,具有单峰单谷波形特征的站点处在非工业城镇或市郊；首次波谷的发生时间均有很好的对应关系(清晨02：00-06：00)；各站点的晴天大气电场强度年变化都具有明显的季节特性：冬季各站点晴天大气电场强度值较大。(2)雷暴地面电场的变化过程对应着雷暴的发生发展过程,而雷暴过程都会呈现出生成期、爆发期和消退期的变化特征,只是每次过程所经历的时间间隔和强度不一样。(3)地面大气电场资料在频域下较时域具有更为明显的特征,通过查看在特征谐波处曲线的峰谷特征以及幅值范围或可作为对首次地闪预报的参数进行参考；将以首次地闪为终值的30分钟电场时间序列的频谱曲线作为基准线,计算多个样本曲线各次谐波处的幅度均值,以此作为标准频谱,使用欧式距离判别法进行预报效果检验,TS技术评分随着预报时间的延长从0.8降低到0.5,证明在短时临近的雷暴预报中是有效的。更多还原

【Abstract】 The activities of the electric field is closely related with the solar activity, lightning activity, sandstorms and earthquakes, which represents an important characteristic parameters to the areas such as space physics, atmospheric physics and space environment, etc. Research on the electric field data in time and frequency domain under different weather conditions is helpful for us to analyze weather processes and forecast the first CG flash.The work is supported by China Commonweal Industry Research Project. Under the premise of using Jiangsu Province Lightning Detection information and Nanjing Doppler radar data as a supplement to ensure the time of the first CG flash, the paper mainly use the atmospheric electric field data to analyze the variation of the atmospheric electric field under different weather conditions. The conclusions are as follows:(1)The diurnal variation of fair-weather atmospheric electric field exhibit in two ways, one of which is a single oscillation with a peak and trough, and another is a double oscillation with two peaks and troughs. The result shows that the single waveform stations often locate in non-industrial towns or suburban. The first trough of all the stations have a good correspondence between02:00-06:00. The seasonal variation of these data is obviously higher in winter and lower in summer.(2)Thunderstorm development process usually contain three stages:towering cumulus stage, mature stage and dissipation stage. The variation of thunderstorm atmospheric electric field in all stations corresponds with the three stages; but there exists different time interval and electric intensity of different state of affairs.(3)Compared to time domain, the variation of atmospheric electric field has a more obvious feature in frequency domain, by examine the amount of the peak&trough of the characteristic harmonic and the amplitude range maybe regard as a new parameter in weather forecast of thunderstorms. After a large number of samples authentication, the data which choose30minutes before the first CG flash which calculated by FFT can be a standard spectrum to distinguish the two types of weather conditions. Meanwhile, using Euclidean distance method on unknown weather samples to classify the data and examine the results. With the extension of the forecast time, the TS score reduced from0.8to0.5, which shows that this new method can be regarded as a reference to the short-term and approaching first CG flash forecast.更多还原