The Global Electrical Circuit A Review Earle Williams

The Global Electrical Circuit: A Review Earle Williams MIT International Conference on Atmospheric Electricity Beijing, China August 2007

Outline - Global Circuit The two Global Circuits : How are they different? Carnegie Curve vs Thunder Area Robustness of Carnegie Curve for individual days Effects of Bomb tests in the 50 s and 60 s Long-term variations Response of global circuit to global change

Two Versions of the Global Circuit

Classical Analysis of the Global Electrical Circuit Carnegie Curve Thunder Area

Wilson (1920) "Thunderclouds and shower clouds" are the sources for the global current.

A common Assertion: Thunderstorms are the batteries for the Global Circuit Wallace et Hobbs (1977) Williams ( 1988) Blakeslee et al (1989) Vonnegut (1991) Bering et al (1998) Rycroft at al (2000) Reddell et al (2004) Holzworth et al (2005) Hayakawa et al (2006) Kartalev et al (2005) Nickolaenko et al (2006) WILSON (1920) DID NOT MAKE THIS CLAIM

Distinctions in the two Global Circuits

The Global Balance Sheet (at Earth’s surface) Fine Weather Current + 60 C Precipitation + 30 C Lightning - 20 C Point Discharge - 100 C Wormell (1930, 1953)

Vertical continuity of current

Global Lightning is more Volatile than the DC Global Circuit Diurnal Time Scale Carnegie Curve OTD Analysis Annual Time Scale Ionospheric Potential OTD Analysis

Two hypotheses for American Dominance over Africa in the Carnegie Curve 1) Current control by position of magnetic dip 2) equator (Kartalev et al, 2006). 2) Electrified shower curves in South America 3) dominate over Africa.

Measurements (Burns et al, 2005) and Predictions (Kartalev et al, 2006) for Seasonal Variations in the Carnegie Curve

African Lightning Exceeds South American Lightning Williams and Sátori (2004)

Carnegie Curve on Individual Days ? Ralph Markson: We should get the same result every day. Bob Holzworth : We can have factor-of-two fluctuations from one day to the next.

Diurnal Variations of Ionospheric Potential Note similarity with behavior of ‘carnegie curve’ (Markson et al, 1999)

Simultaneously Recorded Electric Field at Two Widely Separated Locations Holzworth et al (1984)

Electric Field at South Pole Observatory (Reddell et al, 2004)

Schumann Resonance Diurnal Variations HEW

Schumann Resonance Diurnal Variations HNS

Impact of nuclear weapons testing on Atmospheric Electicity

Long-Term Variations in Electric Field at Two Sites in England 1955 1966

Global Impact of Radioactive Fallout

Ionospheric Potential and Stratospheric Burden of Radioactive Strontium

Long-Term Variations of Global Current

Downward Trends at Nagycenk (Hungary) and Eskdalemuir (UK) Märcz and Harrison (2003)

Evidence for Reduced Pollution in the UK in the 20 th Century Mc. Intosh (1957) Decline in smoke concentration at Eskdalemuir Novakov et al (2003) Decline in black soot production from 1920 onward Reduced Pollution Enhanced Conductivity Reduced Electric Field

14 Years of Schumann Resonance Intensity

Stability of Electric Field at Kennedy Space Center (Halstead Harrison, GRL 2006)

Air Earth current record at Kew From Harrison and Ingram, 2005 Air–earth current measurements at Kew, London, 1909– 1979 R. G. Harrison, T, W. J. Ingramb. Atmospheric Research 76 (2005) 49– 64

Long-Term Variation of Ionospheric Potential

Global circuit response to Global warming?

Global Warming is Sensitive to Latitude

Anticipated Response of Global Circuit to Global Warming Anticipated sensitivity 10% per 1°C Measured global warming (tropics) 0. 1°c per decade ÞAnticipated rate of increase 1% per decade This may go undetected in a short record

Temperature and Thunder Days, Fairbanks, AK Temperature (°F) 62 60 Summer Average Temperatures, Fairbanks, AK 1950 - 2005 58 56 54 52 Number of Thunder Days 20 15 Summer Thunder Days, Fairbanks, AK 10 5 0 1950 1960 1970 1980 1990 2000 2010

CONCLUSIONS § The ‘DC’ and ‘AC’ Global Circuits are correlated, but do not track each other identically, for well established reasons. § Electrified shower clouds (Wilson, 1920) are fundamental in understanding differences between the ‘DC’ and ‘AC’ Global Circuits. § Nuclear weapons tests in the 1950 -60’s appear to have had both local and global effects on the Global Circuit. § No substantive evidence exists for a long-term decline in the Global Circuit. § The absence of a clear upward trend in the Global Circuit is not inconsistent with the documented upward trend in temperature.