A Boost for Space Weather Research and Forecasting

China's Meridian Project Phase II Passes National Acceptance

The Chinese Meridian Project (CMP), a key scientific infrastructure in China, successfully passed national acceptance for its second phase on Friday, March 20, 2025. This milestone will significantly boost cutting-edge scientific research and provide crucial support for the country's space weather forecasting services.

The CMP, also known as the Ground-based Space Environment Monitoring Network, is the world's first comprehensive ground-based monitoring facility covering the Sun-Earth space from the solar atmosphere to near-Earth space. This region is critical for human space activities and utilization, but catastrophic space weather events can pose significant risks, including satellite failures, communication disruptions, navigation deviations, and power grid failures. Therefore, space weather forecasting and early warning services are of paramount importance.

The project, led by the National Space Science Center, began its first phase in 2008 and completed it in 2012. Phase II construction commenced in November 2019 and now boasts over 30 observation stations across the country and in polar regions.

The CMP-Phase II enables end-to-end tracking and monitoring of 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, contributing to cutting-edge scientific research on the Sun-Earth space environment and fundamental physical processes in space physics.

This phase features advanced devices like the Daocheng Radio Telescope, capturing 3D coronal tomography with a 10-solar-radius field of view; a lidar array for continuous height-resolved detection of atmospheric metastable helium; and the world's first tristatic incoherent scatter radar system for ionospheric computed tomography (CT) scanning and 3D imaging.

Additionally, the CMP-Phase II includes the Chinese Dual Auroral Radar Network (CN-DARN), achieving large-scale continuous detection of ionospheric dynamics in the Asian region's middle and high latitudes. It also features China's first facility dedicated to reconstructing three-dimensional solar wind structures for interplanetary environment predictions.

During its trial operation, the CMP-Phase II has already captured valuable observation data and shared it with the world. Notably, it captured the super geomagnetic storm event in May 2024, recording the entire response of the Sun-Earth space environment to solar activity.

Building on this success, China is launching the International Meridian Circle Program, aiming to achieve all-latitude, all-weather, and round-the-clock observation of the Sun-Earth space environment. This ambitious project will further enhance our understanding and preparedness for space weather events, safeguarding human activities in space and on Earth.