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.