摘要:采用考虑化学气体传输过程的云模式模拟了2014年7月30日发生在安徽滁州境内一次深对流过程，研究深对流活动对不同高度示踪气体的输送及再分布作用。结果表明，在积云发展阶段，强上升气流使得云内源层示踪气体有效地向上输送，对流层中部强的夹卷过程及水平入流使得云外气体入云输送至主要对流区，并在垂直气流的作用下进一步影响各层示踪气体的分布。各层示踪气体均可向上输送至对流层上部，其中对流层中部示踪气体（2.1~4.5 km、4.5~7.5 km和7.5~10.8 km）的向上输送作用与近地层示踪气体（0~2.1 km）的贡献相当。例如，输送到11~13 km的示踪气体有4.9%来自近地层，6.3%来自2.1~7.5 km。此外，近地层示踪气体可在深对流的水平输送下向云侧边界扩散，将局地污染输送到云外周边地区。源层高度位于2.1~4.5 km的示踪气体可下沉输送至近地层，形成新的局地污染。随着源层高度的抬升，示踪气体向下输送作用减弱，其中对流层上层示踪物（10.8~15 km）无法输送到6 km以下。
关键词:深对流/
垂直输送/
示踪气体
Abstract:A cloud model with gases transmission process is used to investigate the vertical transport and redistribution of tracer gases at different altitudes in a deep convective system, which occurred on 30 July 2014 over Chuzhou, Anhui Province. The tracers were efficiently transported upward by large vertical velocity from their initial layer at the cumulus stage. The substantial entrainment and horizontal inflow in the mid-troposphere brought the tracers outside the cloud into the convective core region, and the distribution of tracers was further affected by the convective cloud. The tracers in each level could be transported upward to the upper troposphere, and the contribution of mid-tropospheric tracers (2.1-4.5 km, 4.5-7.5 km, 7.5-10.8 km) was comparable to that of boundary layer tracers. For instance, for the tracers that were transported to the altitude of 11-13 km, 4.9% and 6.3% of them were originated from the boundary layer and the mid-troposphere (2.1-7.5 km), respectively. Furthermore, the tracers at 0-2.1 km could be transported to the side of the cloud, bringing local pollutants to the surrounding areas outside the cloud. The tracers between 2.1 km and 4.5 km altitudes could be transported downward to the boundary layer, generating new local pollution. The downward transport of tracers became weak as the altitude of tracers increased, and the upper troposphere tracers (10.8-15 km) could hardly be transported down to 6 km altitude.
Key words:Deep convection/
Vertical transport/
Tracer gases
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