大气冰核谱对雷暴云微物理过程及起电影响的数值模拟

Numerical Simulation of the Impact of Ice Nucleus Spectra on Microphysical Process and Electrification in Thunderstorms

利用已有的二维对流云模式,讨论了三种不同的冰核谱对雷暴云微物理、起电及电荷结构的影响。模拟结果表明:(1)不同的冰核谱环境对雷暴云中冰相粒子的含量及分布具有明显作用。冰核谱的垂直温区越大,产生的冰相粒子分布越广。在冰核浓度较大的个例中,冰晶和霰粒子的含量高,更多的小冰相粒子出现在海拔更高的区域;(2)高温区冰核的数量会对上升气流速度产生显著影响。高温区的冰核越多,冰相粒子在微物理发展过程中释放的潜热越多,上升气流强,对流发展越旺盛;(3)在低温区冰晶浓度高的谱环境个例中,雷暴云中的非感应起电率和感应起电率高,导致起电量增加。高温区冰核多的谱环境,大量冰晶和霰获得正电荷形成次正电荷区,电荷结构呈现三极性;而高温区冰核少的谱环境,参与起电的水成物粒子少,易形成偶极性电荷结构。

In this paper, we discuss the effect of three different ice nucleus spectral environments on the microphysical, electrification, and charge structure of thunderstorm clouds, using the existing two-dimensional(2-D) cumulus model. Simulation results show that:(1) Different ice nucleus spectral environments have a great influence on the content and distribution of ice-phase particlesin thunderstorm clouds. The larger the vertical temperature zone of the ice nucleusspectral, the wider the distribution of the ice phase particles produced. In the case of a large concentration of ice nucleus, the content of ice crystals and graupel particles is high, more small ice crystals appear in the zone of higher elevations;(2) The number of ice nucleus in high-temperature region has a significant affects the updrafts velocity. More ice nucleus in the high-temperature region leads to more latent heat released by the ice phase particles during the development of the microphysical process, resulting in intensive updrafts and vigorous convection development;(3) In the case of ice nucleusspectral environment with high ice crystal concentration in the low-temperature region, The non-inductive electric rate and inductive electric rate are high in thunderstorm clouds, resulting in increased charge. In the spectral environment with high ice nucleus in high temperature regions, a large number of ice crystals and graupel gain positive charge to form a sub-positive charge zone, and the charge structure exhibits tripolarity;while in a high-temperature zone, the spectrum environment with less ice nuclei and less hydrometeors particles participate in electrification, Dipolar charge structures are easily formed.