【摘要】 为了探讨云滴数浓度对于龙卷发生、发展的影响,利用ARPS(Advanced Regional Prediction System)模式,通过调整云滴数浓度(分别取高3000 cm-3、中1000 cm-3和低100 cm-3)的变化,对2003年7月8日安徽省无为县超级单体龙卷进行理想模拟试验。研究表明:三组试验都模拟出超级单体风暴的特征结构如钩状回波和V型入流缺口;云滴数浓度高的试验中上升气流更强、风暴较先发展且持续时间长,近地面涡度也较其他两组试验更大;从三组试验中找到4个龙卷涡旋,其中云滴数浓度高的试验中有两个,涡旋总持续时间接近30 min,最大近地面风速为46.93 m s-1,最大涡度值为0.42 s-1;高云滴数浓度情况下地面冷池弱,更有利于龙卷产生,并对龙卷的发生、发展有促进作用。更多还原

【Abstract】 Numerical simulations with the Advanced Regional Prediction System(ARPS) model were performed to investigate the impact of DNC(droplets number concentration) on tornadogenesis in the supercell tornado over Wuwei County, Anhui Province on 8 July 2003. The three different droplets number concentrations were 3000 cm-3, 1000 cm-3,and 100 cm-3. Results showed that features of supercell tornado such as hook echo and V-type inflow gap were found in all experiments. However, the thunderstorm in the high DNC experiment with the strongest updraft and vortex developed first and lasted for a significant time. Four tornado vortices were found in the three numerical experiments. Two cases in the high DNC experiment lasted for nearly 30 min, with a maximum near-surface wind speed of 46.93 m s-1 and a maximum vortex of 0.42 s-1. These findings suggest that higher droplets number concentration have a positive effect on the occurrence and development of tornadoes due to the attendant weaker cold pool.更多还原