The appearance of southern spread of inertia - gravity wave in high layer was earlier than the one in low layer . the vorticity and divergence belt take on eight as time processes . the high - layer northeast - southwest vorticity and divergence belt spread towards the south and northwest - southeast vorticity and divergence belt spread towards the north 涡度、散度带随时间出现八字形分布，高层东北?西南向的涡度、散度带有向南的传播，西北?东南向的涡度、散度带有向北的传播。
