An Extended DRP-Based 4DEnsVar Data Assimilation Scheme for the GRAPES Model. Part I: Formulation and Tests

Shujun Zhu1, Bin Wang1,2, Lin Zhang3 and Yongzhu Liu3, (1)Department of Earth System Science, Tsinghua University, Beijing, China, (2)Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China, (3)Numerical Weather Prediction Center, National Meteorological Center, China Meteorological Administration, Beijing, China