摘要
本文应用合成分析方法对５个台风的平缓演变阶段和爆发性发展阶段的环境场作了对比分析。结果表明，在台风爆发性发展时，副热带高压及其反气旋环流增强，台风东部低层风速加大，高空有东风扰动叠加，低空辐合和高层辐散增强，低层水汽能量辐合及台风外围对流性不稳定性增大，低空垂直环流发展。以上因子导致积云对流发展。在弱垂直切变环境下，通过第二类条件性不稳定（ＣＩＳＫ）机制，使台风中心气压急剧下降，气旋性环流显著增强，从而导致台风的爆发性发展。这说明台风爆发性发展是大尺度环流和积云对流相互作用的结果。
The ambient fields in the smooth evolution stage are compared with the explosively developing stage of the composite typhoon composited by 5 typhoons. The results show that in the explosively developing stage, the sub-tropical high and its anti-cyclone circulation are intensified. The low level wind to the east of typhoon increases. The upper air easterly wind disturbace overlays on the typhoon. The low level convergence and high level divergence, and the low level moisture flux convergence, the low level vertical circulation and the convective instability in the ambient field of typhoon are all intensified significantly. The above factors result in cumulus convection development. In the weak vertical shear environment, the conditional instability of the second kind (CISK) mechanism causes the rapid decrease of pressure in typhoon center and significant increase of the cyclonic circulation, so that the explosively developing typhoon may result from the interaction between the large-scale motion and cumulus convections.
出处
《大气科学》
CSCD
北大核心
1995年第4期487-493,共7页
Chinese Journal of Atmospheric Sciences
关键词
台风
爆发性发展
合成分析
环境场
typhoon
explosive development
composite analysis.
