1. a Department of Meteorology and Atmospheric Science, The Pennsylvania State University, University Park, Pennsylvania
2. b Center for Advanced Data Assimilation and Predictability Techniques, The Pennsylvania State University, University Park, Pennsylvania
3. c Key Laboratory for Mesoscale Severe Weather, Ministry of Education, Nanjing University, Nanjing, China
4. d School of Atmospheric Science, Nanjing University, Nanjing, China