Once started, there is a sequence of events within each cell of the storm, each circulation of updraught and downdraught. For instance, the updraught might be started by daytime heating of the ground in summer, to yield fair-weather cumulus (Section 8.6). This grows upwards if the atmosphere is unstable. If it reaches the tropopause, the cell has an area of several square kilometres. This initial growth is called the 'cumulus' stage and lasts 10-15 minutes (Figure 9.5). The top of the cloud then glaciates and
Was this article helpful?