When the negatively buoyant air in the cloud downdrafts reaches the surface, it spreads out horizontally, producing cold pools. A cold pool can trigger new convective cells. However, when combined with the ambient vertical wind shear, it can also connect and upscale them into large mesoscale convective systems (MCS). Given the broad spectrum of scales of the atmospheric phenomenon involving the interaction between cold pools and the MCS, a parameterization was designed here. Then, it is coupled with a classical convection parameterization to be applied in an atmospheric model with an insufficient spatial resolution to explicitly resolve convection and the sub-cloud layer. A new scalar quantity related to the deficit of moist static energy detrained by the downdrafts mass flux is proposed. This quantity is subject to grid-scale advection, mixing, and a sink term representing dissipation processes. The model is then applied to simulate moist convection development over a large portion of tropical land in the Amazon Basin in a wet and dry-to-wet 10-days period. Our results show that the cold pool edge parameterization improves the organization, longevity, propagation, and severity of simulated MCS over the Amazon and other different continental areas.

中文翻译：

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蒸发驱动冷池边缘的云组织和传播参数化

当云中的负浮力空气下降到达表面时，它会水平扩散，产生冷池。冷池可以引发新的对流细胞。然而，当与环境垂直风切变相结合时，它还可以将它们连接并升级为大型中尺度对流系统（MCS）。考虑到涉及冷池和 MCS 之间相互作用的大气现象的广泛尺度，这里设计了参数化。然后，将其与经典的对流参数化相结合，应用于空间分辨率不足的大气模型中，以明确解析对流和子云层。提出了与由下降气流质量通量释放的湿静态能量不足相关的新标量。该量受到网格规模的平流、混合和代表耗散过程的汇项的影响。然后应用该模型来模拟亚马逊盆地大部分热带土地在潮湿和干到湿的 10 天周期内潮湿对流的发展。我们的结果表明，冷池边缘参数化改善了亚马逊和其他不同大陆地区模拟 MCS 的组织、寿命、传播和严重性。