0915号台风“巨爵”近海强度突增的诊断分析

Diagnosis of off-shore sudden intensification of 0915 typhoon Koppu

应用卫星云图和NCEP/NCAR再分析资料,对台风"巨爵"在近海强度突然加强进行分析。结果表明,台风"巨爵"在近海突然加强期间,南亚高压和副热带高压减弱,环境风垂直切变大小为10m/s,南海北部海面温度约为28℃,地面有弱冷空气扩散,台风中心附近正涡度增大和正涡度柱向对流层中上层伸展,台风中心附近高层辐散、低层辐合的范围和强度都在不断增大。

Using satellite image and NCEP/NCAR reanalysis data, the reasons of typhoon Koppu rapidly intensifying near land are analyzed. The results show that, during off-shore sudden intensification of typhoon Koppu, South Asia high and subtropical high are weakened, the environmental wind shear is about 10m/s,sea surface temperature of northern South China Sea is at 28 ℃, weak cold air on the ground diffused, and the vorticity near typhoon center increased vertically to the upper level of troposphere, while near-center convergence on lower level and divergence on upper level are extended and strengthened.