Development of a thunderstorm monitoring system based on atmospheric electric fields and 3D cloud imaging on the ground

Thunderstorms are components of typhoons, linear precipitation bands and supercells, which cause severe wind and flood damage and lightning strikes. Observationally tracking the time variation in their development and decay, which is directly linked to precipitation, is important for understanding and predicting precipitation and lightning discharge activity. However, general C-band radars for meteorological use cannot observe cloud particles, and Ka-band radars require a large amount of money for maintenance because the consumable parts are expensive, and there are also limits to high-resolution observations in the vertical direction because it takes time for spatial scanning. Furthermore, it is difficult to track the occurrence and initial growth of cumulonimbus clouds from the horizontal resolution problem because the cloud top altitude cannot be geometrically obtained from geostationary meteorological satellites. The central Tokyo area is facing the risk of flooding due to the limits of its drainage capacity, and it is an urgent issue to accurately grasp the movement of thunderstorms.

Our research group has achieved results in the measurement of electrostatic fields and lightning discharge radio waves associated with thunderstorm activity in the Metro Manila, as well as in 3D cloud measurement using aircraft and satellites. In this study, we will make use of this experience to construct a system that monitors the charge separation within thunderstorm and the time-dependent changes in the three-dimensional shape of clouds. We will do this by deploying three sets of cloud stereo imaging equipment that combines field-mil electric field sensors and multiple digital cameras to surround an area with a diameter of approximately 20 km in the center of Tokyo.