Funding for this research was provided by:
National Key R&D Program of China (2018YFC1503506)
The Special Fund of the Institute of Earthquake Forecasting, China Earthquake Administration (2020IEF0705)
APSCO Earthquake Research Project (Phase II)
Article History
Received: 1 March 2020
Accepted: 19 September 2020
First Online: 29 September 2020
Declarations
: <b>Author’s Contribution</b> JL analyzed the data and wrote the manuscript. WW proposed the topic, conceived and designed the study. XZ helped in the interpretation. All authors read and approved the final manuscript.<b>Funding</b> This work is supported by the National Key R&D Program of China (2018YFC1503506), the Special Fund of the Institute of Earthquake Forecasting, China Earthquake Administration (2020IEF0705), APSCO Earthquake Research Project Phase II, China Scholarship Fund and ISSI-Beijing.<b>Competing Interests</b> The authors declare that they have no competing interest.<b>Compliance with Ethical Standards</b> The authors declare that our manuscript complies to the Ethical Rules applicable for this journal.<b>Availability of data and materials</b> The GPS TEC data supported by the Madrigal database at the Massachusetts Institute of Technology Haystack Observatory can be downloaded from ExternalRef removed. The F<sub>10.7</sub> index are obtained from the ftp site (ExternalRef removed).