云凝结核对南京及周边地区夏季暴雨影响的模拟研究
投稿时间: 2018-01-11  最后修改时间: 2018-03-10  点此下载全文
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马红云 南京信息工程大学气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室 mhypony@126.com 
韩路杰 南京信息工程大学 comeon0706@163.com 
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:利用WRF3.8.1模式,采用Thompson云微物理参数化方案对南京2014年6月初的一次暴雨过程进行了模拟。设置多组数值试验,并从中选取清洁和严重污染两组试验,对比分析了低、高云凝结核浓度对本次降水的影响。数值试验结果显示:(1)对此次降水过程,Thompson方案有一定的再现能力,对24h累积降水量的模拟整体偏低,并且随着云凝结核浓度的上升,累积降水量增加。较高的云凝结核浓度有利于强降水中心强度增强、降水范围扩大,而对较弱降水中心有相反的影响。(2)云凝结核浓度的增加将抑制云滴向雨滴的转化,使更多云滴被输送到对流层中层,对流层低层的暖云过程被抑制。(3)云凝结核浓度的增加使对流层中层的过冷云水增加,促进过冷云水向霰的转化,也促进雪的淞附过程,这有利于冷云过程的发展。(4)云凝结核浓度的增加对暖云过程有负反馈作用,对冷云过程有正反馈作用。
中文关键词:云凝结核  云微物理参数化  暴雨
 
The impact of cloud condensation nuclei on summer rainstorm: Numerical simulation in Nanjing and the surrounding areas
Abstract:WRF3.8.1 is chosen to simulate a rainstorm process in Nanjing in early June 2014 with Thompson cloud microphysics parameterization scheme. The effects of cloud condensation nuclei (CCN) concentrations on the rainstorm are compared by two numerical experiments which represent high and low CCN concentrations respectively. The results show that: (1) The Thompson scheme has certain ability of reproduction in this precipitation process, although the overall sensitivity experiment underestimated 24h cumulative precipitation, and the accumulated precipitation increased with the enhanced concentration of CCN. The intensity and the precipitation area in stronger rainfall are increased under the polluted condition, but opposite in weaker rainfall. (2) The coagulation of cloudwater is inhibited under the polluted conditions, transporting more cloudwater to the middle troposphere, which reduces the warm cloud precipitation in lower troposphere. (3) The accretion of supercooled cloudwater in middle troposphere promotes the transformation from supercooled cloudwater to graupel and theriming of droplets onto snow with the increasing CCN concentration, which could be conducive to the development of the cold cloud process and delay the terminating time of precipitation from graupel. (4) The increase of the CCN concentrationproduces a negative feedback on the warm cloud process, but a positive feedback on the cold cloud process.
keywords:CCN concentration  Cloud microphysical parameterization  Rainstorm  Indirect aerosol effect
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