On March 28, 2023, the rating results of "Top Ten Progresses in Meteorological Science and Technology in China" were announced. "C-Coupler3 for Earth System Numerical Prediction", an achievement completed under the leadership of Professor Liu Li’s Research Group from the Department of Earth System Science (DESS), Tsinghua University was selected.

The rating, led by the National Alliance for Integration and Innovation of Meteorological Science and Education, aimed at timely recognizing the latest progresses in the field of meteorological science and technology in China, publicizing scientific and technological achievements in meteorology, leading scientific and technological innovation in meteorology, rallying the strength of all parties, and accelerating the modernization of meteorological scientific and technological capabilities and social services. A number of scientific and technological achievements from meteorological departments, universities, research institutes and enterprises in related fields participated in the rating, and more than 100 experts in the field participated in the voting and rating.

Modular coupling architecture of earth system model

C-Coupler3 for numerical prediction of earth system and its sustainable development

The coupled multi-layer earth system model is an important scientific and technological support in many fields such as climate change mitigation and disaster prevention and mitigation. A coupler is a common basic platform to support the interaction between multi-layer component modes and system integration. Although China started the mode research and development almost at the same time with Europe and America, China’s coupler research and development lags behind Europe and America for nearly two decades. Therefore, realizing the independent development and control of couplers is a basic task for self-reliance in the earth system science and technology.

Since 2010, Liu Li's Research Group has been independently developing C-Coupler, and with more than ten years' efforts, the team has completed several versions of domestically produced couplers, lifting China out of the backward situation of basic support software for modelling. Among them, C-Coupler3, a numerical prediction coupler for the earth system built in 2023, has achieved key technological innovations such as global kilometer-level efficient parallel coupling, a common framework for flexible parallel, common software module integration framework, common set coupling assimilation framework and common data inputting/outputting framework. The expert group's evaluation is as follows: this achievement has realized the integrated development of couplers and various frameworks for the first time, and all new technologies and couplers are leading in the world as a whole, having great significance for promoting the high-level scientific and technological self-reliance of numerical prediction of the earth system and related businesses in China.

The Outline of Meteorological High-quality Development (2022-2035) issued by the State Council clearly points out that we should speed up the development of independent and controllable numerical prediction models for the earth system. C-Coupler3 has been applied to the development of numerical prediction of the earth system in China, providing support for the high-quality independent research and development of the next generation atmospheric numerical model (MCV model) of China Meteorological Administration, realizing the modular parallel coupling between the dynamic framework of the model and the physical parameterization process, convenient and efficient data input/output, and integrated and efficient parallel under different types of global/regional grids, and achieving high scalability to 100,000 cores, laying a foundation for building the earth system model with this model as an atmospheric component.

C-Coupler3 is being applied to the research and development of coupling modes and assimilation systems of five national key R&D projects. It supports the modular coupling construction and rapid start-up of regional sea-air billow coupling systems of a certain unit of the People's Liberation Army, the First Institute of Oceanography of the Ministry of Natural Resources and the National University of Defense Technology, and lays the foundation for upgrading the existing coupling modes of China Meteorological Administration, National Marine Environmental Forecasting Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Sun Yat-sen University, Tsinghua University and other units.

The series of C-Coupler couplers represented by C-Coupler3, as a significant achievement in China's basic research since the Period of the 13th Five-Year Plan, was selected into the National Science and Technology Innovation Achievement Exhibition during the Period of the 13th Five-Year Plan and included in the China Basic Research Development Report 2022, which covered less than 90 achievements, including less than 20 achievements in the field of earth system science.

This achievement was jointly completed by the Department of Earth System Science and the Department of Computer Science of Tsinghua University, with the main contributors including Liu Li, Sun Chao, Yu Xinzhu, Yang Guangwen, Wang Bin, Yu Hao and Li Ruizhe. The research was supported by the National Key Research and Development and the National Natural Science Foundation of China.

Written by Liu Li

Edited by Wang Jiayin

Reviewed by Geng Rui