Development of 1km-Scale Operational Model in South China

To support short-range weather forecasts, a high-resolution model (1km) is developed and technically upgraded in the South China Regional Center, including the improvement of the 3D reference scheme and the predictor-corrector method for semi-implicit semi-Lagrangian (SISL) in model dynamical core, as well as the improvement of physical parameterization. Furthermore, the multi-process parallel I/O and parallel nudging techniques are developed and have facilitated rapid updating in the assimilation prediction system and fast-output post processing process. The experimental results show that the improved 3D reference scheme and upgraded physic schemes can effectively improve the prediction accuracy and stability with a longer integration time step. The batch test shows that the precipitation forecast performance of 1-km model is significantly better than that of 3-km model. The 1-km model is in operation with a rapidly updating cycle at 12-minute intervals, which can be applied to short-range forecasts and nowcasting.