Xiukuan Zhao1,2*, Baiqi Ning1,2, Lianhuan Hu1,2 and Haiyong Xie1,2
*1Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
2Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China


Among all kinds of ionospheric data, ionogram from the vertical sounding measurement is the one with longest history for ionospheric observation and research. Wuhan ionospheric observatory (30.5°N, 114.6°E) is the oldest ionosonde station in China. It started to operate in 1946 and has made continuously ionospheric vertical sounding for nearly 70 years since then. A large amount of ionogram data have been accumulated, among which 46 years' data were stored in analog way, including 11 years on coordinate papers (1946-1956) and 35 years on 35mm film (1957-1991). Since 2009, the WDC for Geophysics, Beijing has made an effort to archive and digitize the analog ionograms. The film ionograms were scanned into images and converted to digital ionogram. The ionospheric parameters and electron density profiles were retrieved from manually ionogram scaling. The main purpose of this work is to preserve the valuable historical data in digital format and make better use of the digitized data for long term ionospheric research. A series of analysis methods and software have been developed for displaying, annotating, checking and converting the ionogram images. 1,160,000 film ionograms from 1957 to 1991 and 95,000 coordinate paper ionograms during 1946-1956 in Wuhan, China are digitized and archived.

Aiming at managing and sharing the ionosphere data and its derivatives of different stages and different types, a data sharing system has been designed. The core metadata standard of ionosphere data is developed. The system is realized under J2EE environment using programming languages such as JSP. It provides users with various data querying mode according to the relation among types of ionosphere data, and also with many other functions such as online data viewing, automatic generation of data report and statistic figure.

Besides the processing of ionospheric data, we have also dealt with the historical geomagnetic data, meteor radar data, and GNSS data. The historical geomagnetic data have been converted to the IAGA2002 Data Exchange Format. The GNSS data have been converted to Rinex format. Then, all the data stored by WDC for Geophysics, Beijing can be easily shared to the users.

We also host the mirror sites of Madrigal Database ( and DIDBase ( The Madrigal Database is an upper atmospheric science database used by groups throughout the world and it is developed by the MIT Haystack Observatory. The DIDBase is created by the University of Massachusetts Lowell. It provides accurate specification of the electron density in the Earth's ionosphere at more than 60 locations in the world.


The research was supported by the CAS Key Technology Talent Program. We acknowledge the use of data from the Chinese Meridian Project, and the Data Center for Geophysics, National Earth System Science Data Sharing Infrastructure.