The manifestation of the Madden-Julian oscillation in global deep convection and in the Schumann resonance intensity

This study determines the relationship between intraseasonal oscillations o bserved in two independent measures of global lightning activity: a global mean convective index (a proxy for deep convection) derived from the Goddar d Television Infrared Observational Satellite (TIROS) Operational Vertical Sounder (TOVS) Pathfinder infrared cloud observations, and Schumann resonan ce magnetic intensity recorded at Arrival Heights, Antarctica. The study wa s initiated when previous results indicated a possible link between intrase asonal variations in Schumann resonances and variability of sunspot numbers on the timescale of the solar rotation period. The authors used seven year s (1989-95) of daily records, though the Schumann resonance record had a nu mber of gaps. Results of cross-spectrum and composite analysis show that in traseasonal oscillations in deep convection modulate the global variations in the Schumann resonance intensity. In the Tropics, the intraseasonal wave in deep convection has a wavenumber-1 structure with the region from 120 d egrees W to 60 degrees E having one phase, while the other hemisphere has t he opposite phase. The Schumann resonances are enhanced when a maximum in d eep convection lies in the former hemisphere that comprises the main lightn ing-producing regions of South America and Africa. Conversely, Schumann res onances are suppressed when the convection propagates eastward to the India n Ocean and the western Pacific Ocean. This relationship between the deep c onvection and Schumann resonances was best defined during the Northern Hemi sphere springs of 1990 and 1992 but was less evident in 1993 and 1994.