The full scope of the research possible with WWLLN, from the global electric circuit to lightning in hurricanes, can be seen in the publications list.

Lightning Climatology

WWLLN continously monitors global lightning and has been operational since 2004. With the global coverage the climatology of lightning and various temporal and spatial scales can be investigated. For example semi-annual varaitions like the Madden Julian Oscillation (MJO) to diurnal timescales. One set of lightning climatologies show the dirurnal behavior of lightning for many locations around the world at different spatial scales.

Atmospheric Electricity Background

Since the early days of studying magnetospheric electric fields using high altitude balloon payloads, we found that a much of our data was dominated by local thunderstorms, and therefore not useful for the magnetospheric physics study. However, Prof. F. S. Mozer (UC Berkeley) realized that these vector electric field measurements at 30 to 35 km altitudes over thunderstorms were the first vector field measurements of their type. Thus began a new research study of the upward influence of dc and ac fields from thunderstorms on the upper atmosphere, ionosphere and magnetosphere. Prior to these balloon flights in the 1965 to 1980 range, it was thought that the highly conducting ionosphere effectively isolated tropospheric electrodynamics from magnetospheric physics, and vice versa. Of course, we understood that lightning generated waves could couple into ionospheric whistler mode waves, and, in the rare case find a magnetospheric plasma duct allowing propagation to the equator, where it was understood that trapped electrons with matching Doppler shifted frequency to the wave frequency could give energy to the waves. Additionally, it was believed that global circuit currents, generated in the troposphere, could close through the ionosphere and magnetosphere, but these current densities were so small they would be hidden in the much larger ionospheric current systems, such as the Sq currents, or auroral currents.

Lightning generated waves in the upper atmosphere and ionosphere were considered a kind of test wave which triggered wave growth, but which were probably not energetically important by themselves (without the amplification by the particles). Much of this early thinking changed with the in-situ measurement of electric fields in the D and E region ionosphere directly over thunderstorms by Prof. M. C. Kelley. With initial rocket flights up to 150 km over thunderstorms it was found that lightning generated electric field waves were of an amplitude (10s of mV/m) much larger than the ambient fields at midlatitudes. Thus began a decades long effort to study the upward coupling of electromagnetic energy from thunderstorms and lightning into the upper atmosphere, ionosphere and magnetosphere. With the discovery of discharge phenomena in the mesosphere (red sprites, etc, first imaged by Prof. Jack Winckler, U. of Minnesota, and subsequently shown to be easily detected from our backyards (so to speak; Dr. Walt Lyons, FMA Research, Colorado) the field of upward coupling of atmospheric electrodynamics became a very active research topic.

Since those days, our group has been involved with major advances in the field, fostered by the satellite-borne wave-particle measurements (Blackbeard/Alexis, FORTE, and C/NOFS, and by global, real time lighting lightning detection system (WWLLN).