The scale of tropical clouds

The scale of tropical clouds varies greatly, including mesoscale and small scale, mesoscale and weather scale (see weather system). The cloud cluster itself consists of a convective cloud system with a scale of 10 ~ 100 km and a small convective cloud system with a scale of 4 ~ 10 km and a life span of 30 minutes to several hours (that is, a cumulonimbus tower). The convective cloud system in the vertical direction can generally be divided into three layers: ① Inflow layer. In the atmospheric boundary layer, water vapor is transported from the top of the boundary layer to the vertically moving layer through the frictional convergence of the boundary layer airflow. ② Vertical movement layer. Water vapor condenses in this layer, releasing a lot of latent heat, which makes convective clouds develop further. ③ Outflow layer. Above the vertical movement layer, the cirrus cloud with a thickness of about one kilometer diverges outward, and the divergent airflow sinks outside the cloud, forming a convective circulation circle inside and outside the cloud. The number of small and medium convective cloud systems in a cloud cluster greatly exceeds that of medium convective cloud systems. In the process of moving with the prevailing wind (the moving speed is less than the wind speed), this small and medium-sized convective cloud system often forms on the upwind side, disappears on the downwind side and is constantly metabolized. However, it often stays still on the high-temperature sea surface, and sometimes there will be cloud accumulation, which will lead to heavy rain.