2018年8月5日印度尼西亚地震震前电离层异常特征

Characteristics of ionospheric anomalies before the earthquake in Indonesia on August 5,2018

基于2018年8月5日印度尼西亚地震震中(116.45°E,8.33°S)附近的澳大利亚达尔文站和位于震中磁力线共轭区域的武汉站的电离层测高仪观测数据,以及相同区域全球卫星导航系统接收机的观测数据,对该地震震前的电离层异常扰动特征进行了分析。结果显示,震前同时观测到了电离层F2层临界频率(foF2)和总电子含量(TEC)时间序列的异常。基于岩石圈-大气层-电离层直流电场耦合模式和美国国家大气研究中心的热层-电离层环流耦合模式(NCAR/HAO TIEGCM)对震前震中及其对应磁力线共轭点区域的电子密度异常进行了模拟,模拟结果表明,在地震异常电场的作用下,地震区域及其对应半球的磁共轭区域的TEC和电离层F2层峰值电子密度NmF2发生了明显扰动。

Based on the observations of the ionosondes at the Darwin station in Australia near the epicenter(116.45°E,8.33°S) of the earthquake in Indonesia on August 5,2018 and at the Wuhan station in the magnetically conjugated area of the epicenter,and the observations of the GNSS receiver in the corresponding regions,this paper analyzed the characteristics and the mechanism of the ionospheric anomaly disturbance. The results show that both the critical frequency(foF2) and time series of the ionospheric total electron content(TEC) were observed to be abnormal before the earthquake. Based on the lithosphere-atmosphere-ionosphere DC electric field coupling model and thermosphere-ionosphere-electrodynamics general circulation model(TIEGCM) from the National Center for Atmospheric Research(NCAR/HAO),the electron density anomalies of the seismic area and the magnetically conjugated area before the earthquake are simulated. The simulation results show that TEC and maximum electron density NmF2 of the seismic area and the magnetically conjugated area are significantly disturbed by the abnormal electric field before the earthquake.