3D location estimation of lightning charges using electrostatic field changes

Floods caused by the development of cumulonimbus clouds cause significant damage, especially in tropical areas, such as the Southeast Asian region. Lightning strikes in cumulonimbus clouds have been shown to correlate with a time lag of several tens of minutes preceding heavy rainfall. Therefore, it is expected that lightning observations will help us to forecast heavy rainfall. Especially, if we could know the 3-dimensional distribution of lightning charges, this information might be a good proxy way of knowing thunderstorm development.  Here, we improved 3D estimation of lightning charges using electrostatic field measurement. In this method the electrostatic field changes caused by lightning stroke are observed with a network consisting  of sensors installed at multiple locations at about 5 km interval. Based on those data, three-dimensional location and amount of charges removed by lightning stroke can be estimated. A previous study using same kind of data conducted a brute force calculation, which is not practical because it takes about 2 minutes longer than the typical interval of lightning stroke in the active thunderstorm. In this study, we propose a new method using interpolation analysis by kriging, which results in significant reduction of the estimation time to about 8 seconds. This improving will allow us to analyse more data we took so far and make the new model of thunderstorms.

This research is supported by Science and Technology Research, Partnership for Sustainable Development (SATREPS), Japan Science and Technology Agency (JST) / Japan International Cooperation Agency (JICA).