The global atmospheric electric circuit – an overview Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space The global atmospheric electric circuit – an overview Michael J. Rycroft1 and Anna Odzimek2 1CAESAR Consultancy, 35 Millington Road, Cambridge CB3 9HW, and Centre for Space, Atmospheric and Oceanic Science, University of Bath, Bath BA2 7AY, U.K. 2Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, U.K. “What the imagination seizes as beauty must be truth” John Keats, poet (1795-1821)   “Imagination is the highest kite one can fly” Lauren Bacall, actress (1924-present)

ATMOSPHERIC STUDIES FROM THE INTERNATIONAL SPACE STATION Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space ATMOSPHERIC STUDIES FROM THE INTERNATIONAL SPACE STATION

SCHEMATIC DIAGRAM OF THE GLOBAL ATMOSPHERIC ELECTRIC CIRCUIT Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space SCHEMATIC DIAGRAM OF THE GLOBAL ATMOSPHERIC ELECTRIC CIRCUIT Ionosphere Atmosphere Earth’s land/ Ocean surface Rycroft and Fullekrug, JASTP, 2004, Fig. 1

Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space EARLIER ELECTRIC REPRESENTATIONS OF THE GLOBAL ATMOSPHERIC ELECTRIC CIRCUIT Kasemir, 1965 Markson, 1978 Makino and Ogawa, 1984 Nisbet, 1983

Rycroft et al., JASTP, 2000, Fig. 5 Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space Rycroft et al., JASTP, 2000, Fig. 5

Tinsley and Zhou, JGR, 2006, Fig. 2 Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space Tinsley and Zhou, JGR, 2006, Fig. 2

DISTRIBUTION OF POTENTIAL AROUND THUNDERCLOUD Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space DISTRIBUTION OF POTENTIAL AROUND THUNDERCLOUD Rycroft, In Fullekrug et al. book, 2006, Fig. 2

Rycroft et al., JASTP, 2007, Fig. 2 Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space Rycroft et al., JASTP, 2007, Fig. 2

Rycroft et al., JASTP, 2007, Fig. 12; EGU 2008 poster, Fig. 1 Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space Rycroft et al., JASTP, 2007, Fig. 12; EGU 2008 poster, Fig. 1

FAIR WEATHER REGION Rycroft et al., JASTP, 2007, Fig. 15 Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space FAIR WEATHER REGION Rycroft et al., JASTP, 2007, Fig. 15

CARNEGIE CURVE AND THUNDERSTORMS Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space CARNEGIE CURVE AND THUNDERSTORMS Williams, Global electrical circuit, Encyclopedia of Atm. Sciences, 2002, Fig. 3

CARNEGIE CURVE AND NUMBER OF LIGHTNING FLASHES (OTD DETECTOR) Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space CARNEGIE CURVE AND NUMBER OF LIGHTNING FLASHES (OTD DETECTOR) Nickolaenko et al., GRL, 2006, Fig. 4

DIAGRAMMATIC LIGHTNING DISCHARGES (IN RED) Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space DIAGRAMMATIC LIGHTNING DISCHARGES (IN RED) Altitude [ km ] Williams et al., JGR, 2006, Fig. 2

-CG PRODUCING STORM +CG PRODUCING STORM Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space -CG PRODUCING STORM +CG PRODUCING STORM Rycroft et al., JASTP, 2007, Fig. 13

IONOSPHERIC POTENTIAL AFTER LIGHTNING DISCHARGES Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space IONOSPHERIC POTENTIAL AFTER LIGHTNING DISCHARGES Odzimek and Rycroft, EGU 2008 poster, Fig. 2

SPACE-TIME REGIONS AFTER CG DISCHARGE WHERE BREAKDOWN FIELDS EXCEEDED Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space SPACE-TIME REGIONS AFTER CG DISCHARGE WHERE BREAKDOWN FIELDS EXCEEDED Odzimek and Rycroft, EGU 2008 poster, Fig. 3

Odzimek and Rycroft, EGU 2008 poster, Fig. 4 Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space Odzimek and Rycroft, EGU 2008 poster, Fig. 4

Odzimek and Rycroft, EGU 2008 poster, Fig. 5 Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space Odzimek and Rycroft, EGU 2008 poster, Fig. 5

Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space CONCLUSIONS We must strive to understand better all aspects of the Earth’s atmosphere, and how it responds to both external and internal influences (feedbacks). An electrical engineering - software - model of the DC global atmospheric electric circuit, with 1 km vertical resolution, has been constructed; it uses a realistic model of the height profile of atmospheric electrical conductivity. The currents generated by thunderstorms and electrified shower clouds contribute about equally (~ 500 A each) to maintaining the positive potential (~ 250 kV) of the ionosphere with respect to Earth (both good conductors). Lightning does not contribute very significantly (i.e. only ~1%) to maintaining the high potential of the ionosphere, because the effects of + and – cloud-to-ground (CG) discharges essentially cancel each other out. +CGs with significant continuing currents can lead to “carrot” sprites, whereas +CGs with only a return stroke can lead to “column “ sprites. The increased conductivity of the mesosphere (10-7 S/m) associated with a sprite decreases the ionospheric potential by only ~1 V more than for a +CG which is not followed by a sprite.

THANK YOU – ANY QUESTIONS? Corte, 27 June Corsica, 2008 Workshop on Coupling of Thunderstorms and Lightning Discharges to Near-Earth Space THANK YOU – ANY QUESTIONS? E-mail: michaelrycroft@btinternet.com ao64@ion.le.ac.uk News on 7 May 2008: Hot night in Chile: dust and ash from the eruption of the Chaitén volcano explodes into the night sky as an electric storm passes overhead (News, page 27) Photo from http://www.timesonline.co.uk