The nonlinear relationship between lightning activity and temperature

The relationship between temperature and lightning activity is neither direct nor proportional — it is markedly nonlinear. A small rise in temperature in the tropics can lead to a disproportionately large increase in the number of lightning strikes, because heat intensifies deep convection, lengthens and strengthens updrafts and promotes the formation of the ice phase (see #32) Williams 1992.

This strong, nonlinear sensitivity is the reason the Schumann resonance can serve as a "global tropical thermometer": even small changes in tropical temperature show up in global lightning activity — and thus in the intensity of the SR — in an amplified and measurable way Williams 1992.

It is precisely the nonlinearity that makes the SR a valuable tool for monitoring the climate: the SR integrates the signal from all three continental centers at once and responds sensitively to changes in the tropical temperature field, which would otherwise be difficult to monitor globally and continuously.

*Cluster D file — part of the Schumann resonance knowledge base.*