HR: 1330h
AN: AE32A-0166    [PDF]
TI: Which Tropical Continental 'Chimney' Dominates the Global Electrical Circuit, and Why?
AU: * Williams, E R
EM: earlew@ll.mit.edu
AF: Massachusetts Institute of Technology, Parsons Laboratory MIT 48-211, Cambridge, MA 02139 United States
AU: Satori, G
EM: satori@ggki.hu
AF: Hungarian Academy of Sciences, Geodetic and Geophysical Research Institute, Sopron, H-9400 Hungary
AB: Global measures of lightning activity, including classical thunder day observations, optical measurements with the Optical Transient Detector and Lightning Imaging Sensor in space and Schumann Resonance observations are all consistent in showing a predominance of Africa among the three tropical "chimneys". Given the common assumption that thunderstorms are the "batteries" of the global circuit and the Wilson conduction current measurements over thunderstorms (Blakeslee et al, 1989), one expects Africa to dominate the DC global circuit. Yet the classical `Carnegie Curve' and numerous diurnal records of ionospheric potential (Markson) clearly show South America as the dominant chimney. This paradox has resolution in an often overlooked aspect of C.T.R. Wilson (1920) giving special attention to "shower clouds" as contributors to the DC global circuit in addition to thunderstorms. Observations from the NASA TRMM (Tropical Rainfall Measuring Mission) satellite support a greater number of shower clouds in South American than Africa. Further climatological thermodynamic comparisons for surface stations in the Amazon and Congo River basins are examined to understand chimney ranking in lightning and in conduction current. Evidence will be presented that the hotter and dryer characteristics of the most continental chimney (Africa) can account for its factor of two predominance in lightning activity.
DE: 3304 Atmospheric electricity
DE: 3314 Convective processes
DE: 3324 Lightning
DE: 3374 Tropical meteorology
SC: Atmospheric and Space Electricity [AE]
MN: 2003 Fall Meeting