1983 Volume 61 Issue 2 Pages 244-253
Numerical experiments show the following: (1) upward motion induced by a heat island promotes the development of a cumulus, and it can be a trigger to initiate a cumulus; (2) the initiation and the development of a cumulus are so directly affected by conditions of a lower layer modified by the heat island that cumuli which form over heat islands with different horizontal scales behave differently.
Result (1) explains the urban enhancement of cumulus activity shown by climatological studies.