1. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn Previous work (a) shows the MHD (annual station averaged hail days) in China and a sharp decrease is significant from early 80 th. (b) Hail frequency in north China actually decrease from 90 th.

2. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn Previous work 850hPa GPH v-wind composite difference of hail days and non-hail day difference of the period before and after 1990. weak dynamic forcing weak v wind

3. 复旦大学 Impact of environmental factors and microphysics on hail production (real case simulation and sensitivity experiments using WRF) Mingxin Li Department of Atmospheric and Oceanic Sciences, Peking University, Beijing 100871

4. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn 6/11/2005—6/15/2005 observation Location of the cold vortex on 500hPa 6/11/2005—6/15/2005 Case description

5. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn Hail observation on 6/11/2005 UTC 6/11/2005 03 ： 38-08 ： 06

6. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn Model setup 2 nested domain dx=dy=9km 3km 1km Microphysics: Milbrandt 2-mom Simulation time ： 2005-6-10 18:00:00---2005-6-11 18:00:00 （ UTC ）

7. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn D03 accumulated hail precipitation (mm) during one hour and mdbz 2005-6-11 03:00:00---2005-6-11 08:00:00

8. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn

9. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn

10. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn

11. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn

12. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn Sensitivity experiments Reduce initial qvapor by 30% Reduce initial qvapor by 10% Increase initial qvapor by 5% Increase initial qvapor by 10%

13. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn Preliminary results

14. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn Milbrandt 2-moment microphysics scheme 2 parameters

15. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn Preliminary results

16. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn CTR Reduced 30%Increased 10% Total number of grid point

17. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn Next Compare the results of different microphysics scheme Modify environmental factors in the storm

18. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn Thank you

19. PEKING UNIVERSITY Mingxin Li limx@pku.edu.cn