Analysis on characteristics of occurrence and development of strong typhoon Wutip(1321)

Based on the high and low detection data,CIN- Radar and satellite cloud picture data,NCEP reanalysis data,analysis on characteristics of occurrence and development of strong typhoon Wutip( 1321) is made.The results show that Wutip occurs with a screw propeller which is formed by the three level wind shears and the three strong shunts of tropopause on a warm ocean. Propeller rotation being occurred possibly because that absolute vorticity distribution overlaps shear line which is upthrow and vortex,and warm moist air column moves upward in the center of screw propeller. But ulteriorly,the screw propeller rotates because of energy injection and the northeast monsoon enhancing. It is usual to promote that cold advection((- 4—- 25) × 10- 5K·m2·s- 1)and cooling(- 1—- 2 ℃) in the periphery of Wutip,but not that in typhoon kernel. It is worth mentioning that convection,organization and development of cumulus and metabolic typhoon squall in the front of typhoon moving can inspire developing of typhoon. During of typhoon stabilization,ontology structure adjusts so anomaly that typhoon squall is build and involved in inner ring,the spiral cloud bands combine to separate with cloud wall and form a larger range of subsidence area. There is the most dense cloud,the strongest rainfall and the strongest wind under 6 km in different parts of typhoon.