Dear Kai and Xiong, you have properly addressed the reviewer's comment so that your paper is accepted after some technical corrections. In your paper you have many multi-panel graphics, which are generally readable (after sufficient zooming in). Figures 8 and 9 could be improved by arranging a) and b) vertically instead of horizontally. This would allow you to make both graphics a bit larger. At the end you should make sure that for the final PDF, all graphics are legible when zooming in (screen display). This is in particular important for the graphics in Appendix A. Congratulation for a very nice paper. Best wishes, Mark