汶川地震同震电离层扰动研究

We use three ground GPS receiver stations at Xiaguan, Kunming and Luzhou in the CMONOC to study coseismic ionospheric disturbance (CID) for the 2008 Wenchuan earthquake. We retrieve high precise slant total electron content (STEC) through removing the DCB (Difference Code Bias) effect in the line of sight of GPS. Through preproccess of the GPS data and the STEC, we obtained the DTEC time series and the TEC traveling time plots among them. The results show that there exists two CID horizontal propagation speeds in this research. The first is the acoustic speed in the height of ionosphere, about 1.1 km/s, and the second is the secondary CID speed closed to 0.7 km/s, considered to belong to the gravity wave. Finally, using the ray-tracing technique, when the CID speed equals to the 1[KG-*8]000 m/s, the standard deviation of the earthquake onset time can reach the minimum value 19.55s, and the origin of the CID is located at 30.8°N,103.15°E which is about 33.6 km southwest of the Wenchuan earthquake epicenter.