近海台风结构和能量平衡的对比研究

本文以8006和8309两个台风为例，分析了近海台风的结构，指出其重要特点是运动场和热力场的显著不对称和只有弱的暖心。本文还着重对它们在近海及登陆后的总动能和涡动动能收支及加热场情况，进行了对比诊断研究。指出近海台风的不对称结构中，隐含着消亡机制，这是由于不对称的暖区和上升区都偏离台风中心且不相一致，使台风区有效位能向动能转换的过程很弱甚至反向。另外，如台风登陆后继续维持热带系统特点，未能迅速将主要能源由潜热释放转变为斜压过程，也易迅速消亡。在加热场方面，登陆后迅速减弱的台风，最大加热强度较大，其所在层次也较高。

The Study on Structure of the Offshore Tropical Storms and the Comparative Diagnoses of Energy Budget

In this paper, a study on the structure of the offshore tropical storms is made based on the data of the severe tropical storm Ida (8006) and the typhoon Ellen (8309). It is found that the remarkable features of the offshore tropical storms are the obvious asymmetry in the air-flow field and the weak warm center. A comparative diagnostic research on kinetic energy budget and heating field of such a pair of tropical storms is carried out. It is emphatically pointed out that the decay mechanism of an offshore tropical storm is implicated in the asymmetric structure. This is because the warm area and the ascending motion area are biased from the center and not coincided with each other. The baroclinic transformation process from available potential energy to kinetic energy is very weak and even negative. The another decay mechanism is that the tropical storm maintains the characteristics of a tropical system for a long time after landing and then has not rapidly changed the main energy source from latent heat release into the baroclinic process. For the tropical storms which decay soon after landing, the maximum heating is stronger and its altitude is higher.