Observation and interpretation of lightning flashes with electromagnetic lightning mapper

Abstract

We detail concurrent measurements recorded during natural lightning flashes with the ONERA-ITF VHF interferometers, the NASA-LDAR VHF time-of-arrival mapper and the space borne NASA-OTD optical sensor. The development of an intracloud (IC) flash is described based on the measurements of the VHF signal radiated during its occurrence. Optical radiation is compared to VHF radiation recorded during an IC flash and during a negative cloud-to-ground (CG) flash. The results of the analysis suggests that the new ONERA PROFEO lightning mapping sensor which combines both interferometric and time-of-arrival techniques will fit perfectly our observational needs to study the development of lightning flashes, to relate their occurrence relatively to the dynamical and microphysical properties of their parent storms, and to help modelling the multi-scale processes of a lightning flash. We also discuss the weakness of the use of lightning NOx (LiNOx) production per flash for global scale LiNOx estimate. We assess the importance of global lightning detection with respect to having sufficient information about lightning flashes for more realistic estimates LiNOx production. © Springer Science+Business Media B.V. 2009.