The 'Two oceans and one sea' extended range numerical prediction system with an ultra-high resolution atmosphere-ocean-land regional coupled model

The 'Two Oceans and One Sea' area (West Pacific, Indian Ocean, and South China Sea; 15 degrees S-60 degrees N, 39 degrees-178 degrees E) is a core strategic area for the '21st Century Maritime Silk Road' project, as well as national defense. With the increasing demand for disaster prevention and mitigation, the importance of 10-30-day extended range prediction, between the conventional short-term (around seven days) and the climate scale (longer than one month), is apparent. However, marine extended range prediction is still a 'blank point' in China, making the early warning of marine disasters almost impossible. Here, the authors introduce a recently launched Chinese national project on a numerical forecasting system for extended range prediction in the 'Two Oceans and One Sea' area based on a regional ultra-high resolution multi-layer coupled model, including the scientific aims, technical scheme, innovation, and expected achievements. The completion of this prediction system is of considerable significance for the economic development and national security of China.