TY JOUR TI An approach to finding an integral characteristic of ionospheric and lightning activity from WWLLN observational data KW Lightning location KW Earth--ionosphere waveguide KW ionosphere KW lightning KW atmospheric electricity KW instrumentation/sensors JO Russian Journal of Earth Sciences AU , .. AU , .. AU , .. PY 2018 IS 18 PB Геофизический центр Российской Академии Наук