8.The analysis and comparison for 24 cases indicate that the generation and development of most of typhoons are related to western jetstream in equator extending eastward and southern jetstream in east side extending northward.
9.Owe to the coupling of upper and lower tropospheric jet streams , sinking motion to the left side of upper jet streams score and ascent between the right side of upper jet streams score and the left side of the lower jetstream score produce the secondary circulation.