A demonstration of the capabilities of multisatellite observations of oceanic lightning

Abstract

We have examined lightning flashes in five nighttime, oceanic thunderstorms, which were jointly observed by Tropical Rainfall Measuring Mission (TRMM) and Fast On-Orbit Recording of Transient Events (FORTE). The multiplicity of instruments on board these satellites presents a multiphenomenological snapshot view of oceanic nighttime convection. Data are available for five oceanic storms with a total of 40 flashes. The independent optical imagers on each satellite establish the flash locations. The relative fraction of Lightning Imaging Sensor (LIS)-detected optical pulses that were also observed by the FORTE/photodiode detector varied from 0% for LIS range less than 10 4 J sr-1 m-2 μm-1 to 100% for LIS range greater than 106 μJ-1 sr -1 m-2 μm-1. The FORTE/VHF data sometimes allow estimation of the VHF source emissions heights and identification of individual discharge processes as positive or negative, in-cloud or cloud-to-ground. These observations reinforce the concepts that the VHF pulses are produced by a breakdown process, while the optical pulses are the result of current flow. Copyright 2004 by the American Geophysical Union.