基于地面电场资料的雷暴临近预报研究  

Experimental research on thunderstorm nowcasting based on atmospheric electric field data

作　　者：行鸿彦[1,2] 张强[1,2] 季鑫源[1,2] 

机构地区：[1]南京信息工程大学气象灾害预报预警与评估协同创新中心,江苏南京210044 [2]南京信息工程大学江苏省气象探测与信息处理重点实验室,江苏南京210044

出　　处：《大气科学学报》2017年第1期111-117,共7页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金资助项目(61671248);江苏省高校自然科学研究重大项目计划(15KJA460008);中国气象局大气探测重点开放实验室开放课题(KLAS201407);江苏省"信息与通信工程"优势学科平台

摘　　要：利用总体平均经验模态分解算法(EEMD),对南京地区2010—2011年6—8月近地面大气电场资料进行分析,研究了晴天、弱雷暴和强雷暴天气条件下大气电场的振荡特征。在单站电场仪观测范围内,以晴天大气为背景场,根据固有模态函数(IMF)方差最大值对应层数的动态特性,建立并验证了两种强度的雷暴临近预报模型。结果表明:弱雷暴发生前IMF方差最大值对应层数跳变幅度较平稳,而强雷暴跳变幅度逐渐加剧。对IMF方差最大值对应层数进行三次样条插值,可直观地表征雷暴发生发展过程,延长预报时间至1 h。利用这些特征对92个独立样本进行预报效果检验,预报的准确率为73.3%,虚警率为14.5%。Atmospheric electric field instruments can record the entire process of thunderstorms for the creation,development and extinction,based on the principle of conductor induced charges in the electric field.As a result,the instrument scan continuously measure the strength and polarity of atmospheric electric fields for a long period time.In addition,the thunderstorm process is a complex nonlinear chaotic system,which leads to the measured electric field values having strongly nonlinear oscillation characteristics.At the same time,Empirical Mode Decomposition is a new type of nonlinear and nonstationary signal processing method which does not have a pre-determined basis function,and is able to smoothly process the signal based on its own characteristics,which leads to a new concept for ground electric field research.However,atmospheric electric field instruments are susceptible to the effects of the surrounding environment,the observation data quality are severely affected by noise,and model aliasing problems often exist.Fortunately,the Ensemble Empirical Mode Decomposition（EEMD） method has been developed,and is able to resolve these problems by enhancing signal continuity to weaken the mode aliasing effect,and by better reconstructing the amplitude and frequency characteristics of the signal component,based on the Gaussian white noise statistical characteristics.Therefore,this paper analyzes the atmospheric electric field data in the Nanjing area from June to August,2010 and 2011 by means of EEMD,and respectively discusses the oscillation characteristics of the atmospheric electric field in fair,weak and severe thunderstorm weather.In addition,the energy of thunderstorm is found to be far higher than the fair weather,which mainly contains low frequency components.Meanwhile,with the further development of thunderstorm,the electric field energy is mostly concentrated in the high frequency parts.Clearly,the intrinsic mode function（IMF） component variances are significantly different in the three types of weathe

关 键 词：总体平均经验 模态分解 大气电场 方差动态特性 雷电预警 

分 类 号：P457.9[天文地球—大气科学及气象学]