The Chinese Meridian Project (CMP) and the International Meridian Circle Program (IMCP): Overview, Progress, and Achievements

The National Major Scientific and Technological Infrastructure— the Chinese Meridian Project (CMP) — completed its Phase II acceptance and integration with Phases I in March 2025, and has since entered full operation. The project employs a detection architecture consisting of “one chain, three networks, and four focuses”, deploying 282 monitoring instruments across 31 stations within China’s territory and at both poles. This forms a grid-like comprehensive ground-based network monitoring the geospace environment along 100°E, 120°E, 30°N, and 40°N. Currently, this project has the world's most extensive, comprehensive, and capable such network. The data it acquires are openly shared globally, supporting worldwide cutting-edge scientific research on space weather and its warning/forecasting. This article highlights research advances achieved over the past two years using the CMP data, and briefly introduces the International Meridian Circle Program, which is currently being promoted and initiated based on the CMP.