We present model computations of global electromagnetic resonance (Schumann resonance) based on the monthly worldwide distribution of thunderstorm activity collected by the Optical Transient Detector satellite. To obtain diurnal and seasonal variations of electromagnetic signals produced by the thunderstorms worldwide, we apply masks that "activate" definite parts of global thunderstorms and move around the planet with the Sun. Three types of masks are discussed: The first one triggers the activity at the dayside of the globe; the second one activates its afternoon sector; and the third one switches on the thunderstorms within a hot spot, a circular area of a fixed radius. We perform computations of Schumann resonance spectra and demonstrate that numerical models are a useful tool for studying and interpreting resonance features.