东北太平洋一次强爆发性气旋发展的机制分析

使用FNL Analysis全球格点资料,对东北太平洋一次强爆发性气旋的特殊性进行了分析,发现气旋对其西北部低压系统的吸收合并是其爆发性发展过程中的典型特征,斜压强迫对其快速发展的作用较弱,与西北太平洋爆发性气旋的发展过程存在显著差异。同时,使用Zwack-Okossi诊断方程,从影响爆发性发展的动力和热力因子方面,对其发展机制作了深入的探讨。研究表明,正涡度平流、暖平流和非绝热加热的共同作用使气旋开始爆发性发展,由潜热释放导致的非绝热加热的贡献最大,非绝热加热是其快速发展的主导因子,其中正涡度平流贡献主要来自于中高层,暖平流的贡献主要来自于中低层和高层,而非绝热加热主要发生在中低层,这为东北太平洋爆发性气旋的发展机制提供了一个新的认识。

Development mechanism of a strong explosive cyclone over the northeastern Pacific

By using FNL analysis global grid data, the particularity of a strong explosive cyclone over the northeastern Pacific was analyzed carefully. It is found that the absorption and merger of the cyclone to the northwestern low pressure system is a typical feature of its explosive development process, and the baroclinic forcing has a weak effect on its rapid development, which is significantly different from that of the explosive cyclone over the northwestern Pacific. At the same time, the Zwack-Okossi diagnostic equation was used to discuss the development mechanism of explosive development from the aspects of dynamic and thermal factors. Results show that the combined action of positive vorticity advection, warm advection and diabatic heating makes the cyclone explosive development, and the diabatic heating caused by latent heat release makes the largest contribution. Diabatic heating is the dominant factor of its rapid development. The positive vorticity advection mainly comes from the middle and upper levels, the warm advection mainly comes from the middle and lower levels and the upper levels, and the diabatic heating mainly comes from the middle and lower levels. This study provides a new understanding of the development mechanism of the explosive cyclone over the northeastern Pacific.