1. Department of Atmospheric and Oceanic Sciences, School of Physics; Peking University; Beijing China
2. Key Laboratory of Meteorological Disaster of Ministry of Education; Nanjing University of Information Science and Technology; Nanjing China
3. Center for Analysis and Prediction of Storms, School of Meteorology; University of Oklahoma; Norman Oklahoma USA
4. State Key Laboratory of Severe Weather; Chinese Academy of Meteorological Sciences; Beijing China