Monitoring and prediction of terrestrial and space environments using natural andman-made electromagnetic noises
Yasuhide Hobara*Graduate School of Informatics and Engineering, University of Electro-Communications**Center for Space Science and Radio Engineering, University of Electro-Communications
Chofugaoka, Chofu 182-8585, Japan
Email: hobara@ee.uec.ac.jp

In this invited lecture, I would like to briefly introduce how observations of both natural and man-madeelectromagnetic (EM) noise contribute to monitoring terrestrial environments and mitigating natural disasters.
I will focus on three different topics such as (1) lightning discharges, (2) electromagnetic phenomena
associated with seismic activities, and (3) space weather. An interdisciplinary approach is highly required totackle the above-mentioned problems, and so we should closely collaborate with various URSI scientificcommissions.
(1) Lightning discharges
Recent global climate change causes more hazardous meteorological events worldwide. Most of these
events are associated with active thunderstorms with significant lightning discharges. Lightning discharges
generate strong electromagnetic pulses known as sferics in wide frequency ranges and the pulses propagate
a long distance. I am going to demonstrate two practical applications of lightning discharges.
The first application of lightning is to monitor and short-term forecast extreme meteorological events
such as Tornadoes, wind gusts, and heavy rainfall causing flash floods, etc. by using so-called Total Lightning(TL), which is a sum of the Cloud to Ground lightning discharges (CGs) and In-Cloud lightning discharges(ICs). Analyzed results of the TL data from the Japanese Total Lightning Network (JTLN) will be presented.
The second application is related to mitigating the damage to the power grid systems from very energetic
lightning characterized by a large lightning charge Q. Extremely Low Frequency (ELF) range EM radiationfrom lightning are utilized to derive the proxy of Q. Both regional and seasonal dependences in Qds and Ipof CGs provide the basic information to prevent/mitigate potential damages to the power grid systems andrenewable power generating systems. Such examples in Japan and Malaysia will be demonstrated.
Lightning observations from space such as satellites and International Space Station (ISS) can provide
electrical properties of lightning on the ground with uniform and high sensitivity. Such examples from
EM/optical observations will be presented.
(2) Electromagnetic phenomena associated with seismic activities
Significant progress has been made in this new scientific field, exploring the possibility of earthquake(EQ) prediction with EM effects in the last few decades. In this talk, recent results of the various types ofEM phenomena such as lower ionospheric perturbation observed by VLF/LF transmitter signals, ULF/ELF
anomalies, atmospheric electric field, etc. around EQs will be presented.
(3) Space weather
Prediction of physical parameters in the space environment is extremely important not only for space
weather but also for seismo-electromagnetics. Here machine learning techniques are applied to build spatiotemporal models to predict energetic electrons flux in the radiation belt (various external space weather
parameters including ground-based ULF geomagnetic field data), VLF/LF transmitter amplitude, and F2
layer critical frequency (foF2). The prediction accuracy of proposed models is quite high and is proved to beuseful.