Damao Village, Sanya City, Hainan Province, south China - Recent (CCTV - No access Chinese mainland)
1. Aerial shots of Sanya Incoherent Scatter Radar, antenna units
2. SOUNDBITE (Chinese) Yue Xinan, research fellow, Institute of Geology and Geophysics, Chinese Academy of Sciences(starting with shot 1/ending with shot 3):
"To put it more vividly, its detection capability is like being able to observe a candle 300 kilometers away with the naked eye. Each unit of the radar is equivalent to a pixel of an eye. When there are more pixels, the resolution and the accuracy will be higher."
3. Aerial shots of Sanya Incoherent Scatter Radar, antenna units

FILE: China - Data Unknown (CCTV - No access Chinese mainland)
4. Various of animation showing planets, solar activities

Damao Village, Sanya City, Hainan Province, south China - Recent (CCTV - No access Chinese mainland)
5. SOUNDBITE (Chinese) Yue Xinan, research fellow, Institute of Geology and Geophysics, Chinese Academy of Sciences (starting with shot 4/ending with shot 6):
"Since the scattering cross section of electrons is nearly 20 orders of magnitude lower than the space targets we often see, its scattering signal is very weak, which requires the radar to have the capabilities of high power, large aperture, and low noise."
6. Aerial shot of Sanya Incoherent Scatter Radar
7. Various of components underneath antenna units
8. Animation showing operation of Sanya Incoherent Scatter Radar
9. SOUNDBITE (Chinese) Zhang Ning, engineer, Institute of Geology and Geophysics, Chinese Academy of Sciences (starting with shot 8/ending with shots 10-12):
"With the 8320 units, powerful energy can be radiated to the ionosphere, and then the ionosphere will scatter weak echo signals. Through low-noise amplification and waveform encoding and decoding, we can analyze the weak scattering signals and obtain the parameters of the ionosphere, and magnify the state of electrons and ions in the ionosphere to scientists as if through a microscope."
10. Antenna units
11. Device
12. Various of researchers working; computer screens showing monitoring data
13. SOUNDBITE (Chinese) Yue Xinan, research fellow, Institute of Geology and Geophysics, Chinese Academy of Sciences (partially overlaid with shots 14-15/ending with shot 16):
"The main station in Sanya has the emitting and receiving functions. There are also two receiver stations, one in Danzhou City, northwestern Hainan Island, and the other in Wenchang City, northeastern Hainan Island. The three stations have formed an incoherent scatter radar system of 'one emitter and three receivers'. It can be simply imagined as a space-oriented 'super computerized tomography' that can get three CT sections at the same time, which will contribute to monitoring the three-dimensional state of the entire space environment."

++SHOTS OVERLAYING SOUNDBITE++
Hainan Province, south China - Recent (CCTV - No access Chinese mainland)
14. Various of incoherent scatter radars

Damao Village, Sanya City, Hainan Province, south China - Recent (CCTV - No access Chinese mainland)
15. Animation showing operation of incoherent scatter radars
++SHOTS OVERLAYING SOUNDBITE++
16. Aerial shots of Sanya Incoherent Scatter Radar

FILE: Pingtang County, Qiannan Buyi and Miao Autonomous Prefecture, Guizhou Province, southwest China - Date Unknown (CCTV - No access Chinese mainland)
17. Aerial shot of Five-hundred-meter Aperture Spherical radio Telescope (FAST)

FILE: Daocheng County, Ganzi Tibetan Autonomous Prefecture, Sichuan Province, southwest China - Date Unknown (CCTV - No access Chinese mainland)
18. Aerial shots of Daocheng Solar Radio Telescope (DSRT)

China's Sanya Incoherent Scatter Radar (SYISR), the most advanced ground-based ionospheric detection equipment so far in the world, has begun large-scale and multi-parameter monitoring and research.

The SYISR in Sanya City of south China's Hainan Province is a landmark equipment of the Meridian Project, the country's ground-based space environment monitoring network. Comprising over 8,320 antenna units, it covers an area of 1,600 square meters, equivalent to the size of four basketball courts.

"To put it more vividly, its detection capability is like being able to observe a candle 300 kilometers away with the naked eye. Each unit of the radar is equivalent to a pixel of an eye. When there are more pixels, the resolution and the accuracy will be higher," said Yue Xin'an, a research fellow with the Institute of Geology and Geophysics under the Chinese Academy of Sciences.

The expert said that although the electron density in the ionosphere is less than 1 percent of the neutral component, they are very sensitive to the disturbance process in the solar-terrestrial space, such as solar bursts and earthquakes.

The electrons in the ionized layer are regarded as a "display screen" for space weather due to their quick responses to solar activities. Therefore, understanding the state and change mechanism of these electrons in the ionosphere is of great significance to the safety of satellite navigation and communication and even the prediction and warning of earthquakes.

"Since the scattering cross section of electrons is nearly 20 orders of magnitude lower than the space targets we often see, its scattering signal is very weak, which requires the radar to have the capabilities of high power, large aperture, and low noise," Yue said.

The core part of the radar array is the components underneath each antenna unit that can send and receive signals. Under unified instructions, the 8,320 units will radiate electromagnetic wave into the air in the same direction and at the same time, so that the energy will be concentrated and the power will be greater.

"With the 8320 units, powerful energy can be radiated to the ionosphere, and then the ionosphere will scatter weak echo signals. Through low-noise amplification and waveform encoding and decoding, we can analyze the weak scattering signals and obtain the parameters of the ionosphere, and magnify the state of electrons and ions in the ionosphere to scientists as if through a microscope," said Zhang Ning, an engineer at the institution.

The higher the altitude, the thinner and more difficult to detect the density of electrons in the ionosphere. The current ionospheric detection altitude of institutions abroad is several hundred kilometers, but the SYISR, as the world's largest and most powerful phased array incoherent scatter radar, has raised the detection altitude to over one thousand kilometers.

Meanwhile, the SYISR's detection accuracy and sensitivity is also world-advanced, and it can capture changes in finer particles like plasma.

Since it was put into operation earlier this year, the radar array has observed the profile structure of ionospheric plasma cavity with high spatiotemporal resolution for the first time, which has laid a solid foundation for related physics research.

"The main station in Sanya has the emitting and receiving functions. There are also two receiver stations, one in Danzhou City, northwestern Hainan Island, and the other in Wenchang City, northeastern Hainan Island. The three stations have formed an incoherent scatter radar system of 'one emitter and three receivers'. It can be simply imagined as a space-oriented 'super computerized tomography' that can get three CT sections at the same time, which will contribute to monitoring the three-dimensional state of the entire space environment," Yue said.

In addition, as a high-power radar, the SYISR is also an ideal signal source for other radio astronomy equipment. It has started cooperation with China's Five-hundred-meter Aperture Spherical radio Telescope (FAST) and the Daocheng Solar Radio Telescope ring array to conduct joint observations. They have initially achieved a number of results.

It is understood that in the next step, the SYISR will expand its capabilities to monitoring the moon and small celestial bodies.