Anomalies of land-atmospheric parameters in the 2023 Turkey earthquake (Mw7.8) using GNSS and ERA5

The Turkey earthquake (Mw 7.8) caused severe damage to Turkey and Syria on Feb. 6, 2023. It was observed that anomalies of land surface and atmospheric multi-parameters were associated with the land–atmosphere–ionosphere coupling (LAIC) mechanism. The data from the Global Navigation Satellite System (GNSS) and the fifth-generation ECMWF reanalysis (ERA5) were employed to establish two GNSS precipitable water vapour (PWV) interpolation models using Random Forest (RF) and extreme gradient boosting (XGBoost) algorithms. Anomalous variations of land-atmospheric parameters were analyzed using Sliding Interquartile Range (SIQR) and Z-score (ZS) methods. The results show that the root mean square errors (RMSEs) of the RF-PWV and XGBoost-PWV are 1.15 and 1.32 mm, respectively. On Feb. 5, the maximum ZS values of the surface latent heat flux (SLHF) and total column water vapour (TCWV) reached 20.03 and 4.71, respectively. On Feb. 6, the ZS of air temperature (AT) and surface pressure (SP) reached extremes of 4.18 and −7.87, respectively. The PWV decreased rapidly 1 h before the earthquake and recovered quickly to its peak thereafter. Small anomalies (≤1.61 TECU) in total electron content (TEC) were detected on Feb. 4–5. However, substantial increases in the number and magnitude of the TEC anomalies were observed on Feb. 6, with a maximum of 14.83 TECU.