The Global Circuits Paradox

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The long-term sustainability of Earth calls increasingly for a global perspective. This research involving simultaneous measurements of the two global circuits is decidedly global in nature. The two globally invariant (at any given time) quantities under study are (1) the ionospheric potential, representing the totality of electrified weather and (2) Schumann resonance activity, the global totality of lightning, both of which are experienced by all of humanity. Thunderstorms and lightning are both threats to all human activity, and so deserve to be monitored. The monitoring of the Earth’s Schumann resonances lends itself naturally to international cooperation. Both global electrical circuits have been shown to be responsive to surface air temperature on a variety of time scales, with much relevance on longer time scales to fossil fuel consumption and global warming given these natural frameworks for global monitoring. The observed trends will be of value to policy makers. The interest in the variable source strengths of continental “chimneys” (continental scale regions of strong convection) is also directly linked to the large-scale circulation of the atmosphere, and hence global weather patterns are likely linked with the global circuit variations under investigation here. Thunderstorms are important players in global warming because they produce large areas of cirrus cloud that affect incoming solar radiation, and also redistribute water vapor from the planetary boundary layer to the upper troposphere where it is radiatively more important. A critical aspect of global heat balance also lies with tropospheric aerosol and this study is the first to take on the monitoring of cloud condensation nuclei (CCN) on the spatial scale of the continental chimneys.A large body of evidence, some of it a century old, supports the view that the ionospheric potential characterization of the DC (“Direct Current”) global electrical circuit is maximum over the diurnal cycle in Universal Time (UT) when the American continent is electrically predominant near 19-20 UT. In contrast, a comparable body of evidence shows that global lightning activity, and the AC (“Alternating Current”) global circuit (aka, Schumann resonances) is maximum when Africa is electrically predominant (14-15 UT). This apparent contradiction is referred to hereafter as the “global circuits paradox”. This research is aimed at a resolution of this paradox. The thesis of this investigation is that the “global circuits paradox” has long gone unresolved because essential quantities have not been examined in comparisons of contributions from America and Africa, the dominant chimneys driving the global circuits. Thermodynamic contrasts have previously been examined and fall short in resolving the paradox. Electrified shower clouds were identified as possible fundamental sources additional to thunderstorms for the DC global circuit by C.T.R. Wilson, but careful comparisons between America and Africa are only recently possible with satellite and lightning observations. Increased pollution in the form of CCN have been shown to increase lightning flash rate in thunderstorms in both observations and models, but only recently have CCN been accessible on the continental scales relevant to the global circuits. In this study, coordinated measurements of the DC and AC global circuits when Africa and America are most prominent, together with electrified shower clouds and CCN (and with appropriate controls on thermodynamic quantities) to resolve the global circuits paradox.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.