台风登陆衰减后造成降水加强的概况

对1965-2008年101例登陆台风衰减后3d内仍存在较强降水的天气过程,运用客观分离方法及其改进方案,分离提取了台风降水(Tropical Cyclone Precipitation；TCP),结果表明:即使登陆台风衰减为热带低压或停编后,因台风系统的存在而产生高强度降水是一种普遍现象,仍旧是预报服务中需要高度关注的问题.采用气候趋势系数和功率谱等方法得到TCP及台风的气候特征:台风衰减点的位置分布具有很强的区域性,与南岭、武夷山脉的走势大致吻合；台风衰减后降水并非单纯性减少,随着时间的推移,空间分布具有向北、向西扩散的特点,特别是中纬度地区的江汉一江淮一带,仍然是防灾减灾的重点.对于衰减后降水反而加强的台风,防御重点可以有针对性地对登陆华南类和登陆华东类两类路径的台风展开.

Summary of causing increase in precipitation by landfalling weakened tropical cyclone

The landfalling tropical cyclone precipitation (TCP) during 3 d after its weakening is partitioned from the 101 landfalling TCs from 1965 to 2008 with the Objective Synoptic Analysis Technique and its improvement programs. The results show that, even if the landfalling TCs attenuate to a tropical depression or tend to be dead, high-intensity rainfall caused by the presence of the typhoon system is universal phenomenon. So it still requires a high degree of concern. The climate characteristics of TCP and TCs were analyzed with trend coefficient and power spectrum technique. The spatial distribution of TCs' weakening spots shows great regionalization, which is obviously consistent with terrain. The volume of landfalling weakened TCP does not monotonously decrease with time, and the distribution of TCP spreads westward and northward. Especially, more emphasis should be paid on precipitation from Jiang-Han to Jiang-Huai area in middle-latitude, which is the point to reduce and prevent disasters. The TC tracks of landfalling south and east China should be focused on, in order to limit the damage caused by landfalling weakened TCs.