Analysis of Pre-Earthquake Space Electric Field Disturbance Observed by CSES

In order to explore the abnormal disturbance of space electric field caused by earthquakes using data ULF and VLF frequency bands observed ZH-1 satellite, taking Mw7.7 earthquake in Caribbean Sea southern sea area Cuba on 29 January 2020 as an example, signal-to-noise ratio NAA NLK artificial source transmitting stations Northern Hemisphere height lower ionosphere was calculated. The band extracted S-G filtering method. results indicate that: (1) ionospheric anomaly this appeared 20 days before earthquake, there were significant anomalous changes all parameters within pregnant seismic zone. ratios transmitter decreased 30%, low 5–10 km, while perturbations several orbits field, magnitude exceeded three times standard deviation. (2) SNR after significantly reduced third period recovered earthquake. (3) appears be recovers (4) decrease S/N occurred simultaneously with 15 days–10 This provides a reference for extracting pre-earthquake precursor anomalies.