Preliminary results of the ionospheric high-frequency Doppler shift monitor for the Phase II of Chinese Meridian Project

The Phase II of Chinese Meridian Project plans to construct ionospheric Doppler sounding arrays around Mohe, Beijing, Wuhan, and Shenzhen. Each array consists of one transmitter station and three stations equipped with the ionospheric high-frequency Doppler shift monitor, which is described in this paper in terms of system design and preliminary results from its pilot operation. By comparison with a collocated ionosonde, the performance capability of the sounder is validated. At present, the sounders have been installed at seven stations and have been running continuously for about 1 year. This paper presents observations of various ionospheric disturbances caused by solar flare eruptions, travelling ionosphere disturbances, and probable large-scale electric field variations. Once established, the chain of sounder arrays will continuously monitor ionospheric disturbances over eastern China and contribute to the sophisticated space environment monitoring network of the Chinese Meridian Project.