One of China's key scientific infrastructures, the Chinese Meridian Project (CMP), successfully passed national acceptance for its second phase on Friday. It will boost cutting-edge scientific research and provide key support for the country's space weather forecasting services, according to the National Space Science Center of the Chinese Academy of Sciences.

The project, also known as the Ground-based Space Environment Monitoring Network, is the world's first comprehensive ground-based monitoring facility to cover Sun-Earth space from the solar atmosphere to near-Earth space.

The Solar-Terrestrial space is the main area where humans conduct space activities and utilize space. Catastrophic space weather can lead to significant risks such as satellite failures, communication disruptions, navigation deviations, and power grid failures. As a result, space weather forecasting and early warning services are of great importance.

The project is led by the National Space Science Center. The CMP-Phase I started in 2008 and was completed in 2012, the CMP-Phase II began construction in November 2019. The project has over 30 observation stations, covering the country as well as the polar regions.

The project realizes the end-to-end tracking and monitoring capabilities for solar storms from the solar atmosphere to near Earth space. It provides key and independent data for China's space weather forecasting and early warning services and contributes to cutting-edge scientific research, including the overall change mechanism of the Sun-Earth space environment and the basic physical processes of space physics.

The CMP-Phase II consists of a batch of advanced devices, including the Daocheng Radio Telescope that captures 3D coronal tomography with a 10-solar-radius field of view; a lidar array for continuous height-resolved detection of atmospheric metastable helium within a height range of 200 to 1,000 km; and the world's first tristatic incoherent scatter radar system that conducts ionospheric computed tomography (CT) scanning and 3D imaging over distances of thousands of kilometers.

The CMP-Phase II also features the Chinese Dual Auroral Radar Network (CN-DARN), a mid-latitude high-frequency radar array which achieves the large-scale continuous detection of ionospheric dynamics in the middle and high latitudes of the Asian region, filling the monitoring gap of previous SuperDARN; and the country's first facility dedicated to reconstructing three-dimensional solar wind structures for interplanetary environment predictions.

During the trial operation, the CMP-Phase II has already obtained observation data and shared them with the world. For instance, it captured the super geomagnetic storm event in May 2024 and recorded the entire process of the Sun-Earth space environment's response to solar activity.

Based on the project, China is launching the International Meridian Circle Program, with the goal of realizing an all-latitude, all-weather, and round-the-clock observation of the Sun-Earth space environment.