台风“天鹅”对“莫拉克”台风暴雨增幅影响的模拟分析

Simulation analysis of typhoon Goni's enhancement effect on heavy rainfall in Taiwan by typhoon Morakot

就2009年8月台风"天鹅"对"莫拉克"台风暴雨增幅的影响问题进行客观分析,并通过WRF数值模拟试验的方式进行研究探讨.利用NCEP/NCAR客观再分析资料分析发现"莫拉克"台风从"天鹅"台风环流中获取正涡度和水汽供应,有利于其台风强度的长期维持,是造成台湾地区超强降水的重要条件之一.进一步运用WRF数值模式对剔除"天鹅"台风的敏感性试验进行诊断分析,发现"天鹅"台风向"莫拉克"台风环流中有正涡度及水汽供应,与客观分析较为一致,最终估算出"莫拉克"台风在台湾地区南部造成的超强降水中有近三成来自于"天鹅"台风的动力和水汽贡献.

The quantitative impact in terms of moisture supply of typhoon Goni on heavy rainfall of typhoon Morakot in Taiwan has been studied in the paper using the weather research and forecasting（ WRF） numerical model based on NCEP / NCAR reanalysis data.The numerical analysis indicates that the intensity of typhoon Morakot was enhanced by continuously positive vorticity and water vapor supply from typhoon Goni that kept the persistent power of typhoon Morakot during its lifetime in Taiwan.The results of the simulation are consistent with the observations.Furthermore,a specific experiment of WRF numerical simulation in which typhoon Goni was filtered out was carried out,which shows that the typhoon Goni contributed about 30% in power and water vapor to the heavy rainfall of typhoon Morakot in Taiwan.