云凝结核浓度对不同强度南海热带气旋强度影响的个例模拟研究

CASE STUDIES ON THE INFLUENCE OF CLOUD CONDENSATION NUCLEI WITH DIFFERENT INTENSITYES ON THE INTENSITY OF TROPICAL CYCLONES IN THE SOUTH CHINA SEA

关键词:  南海热带气旋  气溶胶  CR-WRF模式  强度

Key words:  South China Sea tropical cyclone  aerosol  CR-WRF model  intensity

摘要:

利用云分辨天气研究和预报模式（CR-WRF）模拟在清洁大气和污染大气下，气溶胶的云凝结核作用对不同强度南海热带气旋（TC）的强度变化影响，对比分析了动力结构和微物理结构的变化。(1) 在污染大气环境中，更多气溶胶能进入到弱TC内部云带区，并充当凝结核作用，TC内部各相态水凝物含量都有明显增多,释放潜热有利于TC内部的对流发展，弱TC中心海平面气压下降，强度加强。（2） 在污染大气环境中，气溶胶主要影响强TC的外部螺旋云带区；外部云带区各相态水凝物增多，释放潜热有利于该处对流的发展；外部云带区对流与云墙区内对流形成竞争，导致入流减弱，云墙区内上升运动减弱，强TC中心海平面气压上升，强度减弱。

Abstract:

A cloud resolving Weather Research and Forecasting (CR-WRF) model is employed to simulate the effects of cloud condensation nuclei with different intensities on the intensity of tropical cyclones (TC) in the South China Sea under clean and pollute atmospheres. With the comparison of the changes of the dynamic and micro-physical structure, the following conclusions are drawn. (1) In polluted atmosphere, more aerosols enter weak TCs and act as condensation nuclei. The content of hydrometeor in different phases significantly increases. The release of latent heat is conductive to the development of convection within weak TCs. This leads to a decrease in the sea level pressure in the center and an increase in the intensity of weak TCs. (2) Aerosols mainly affect the areas outside the cloud wall of strong TCs. More hydrometeor outside the cloud wall area is generated, releasing more latent heat, which is conducive to the development of convection there. Because of the competition between the convection inside and outside the cloud wall area, both the inflow into the TC center and the upward movement in the cloud wall are weakened. As a result of this effect, the sea level pressure in the center increases, while the intensity decreases.