SIMULTANEOUS DISTURBANCE OF CONJUGATE IONOSPHERIC REGIONS IN ASSOCIATION WITH INDIVIDUAL LIGHTNING FLASHES

Characteristic whistler‐associated amplitude perturbations of subionospheric VLF or LF signals (“Trimpi events”) observed within one second of each other at Palmer Station, Antarctica and at Arecibo, Puerto Rico suggest that ionospheric regions in both northern and southern hemispheres are disturbed together in association with individual lightning flashes. During a one hour period on March 21, 1989, the onsets of 44 out of 47 perturbations measured on a 21.4 kHz signal from Maryland to Arecibo occurred within l s of perturbation onsets measured on a 23.4 kHz signal from Hawaii to Palmer Station. Similar activity occurred before and after this period, and on the preceding and following days. The observations are consistent with the disturbance of geomagnetically conjugate ionospheric regions by multiple bounces between hemispheres of bursts of radiation belt electrons, scattered in pitch angle by whistlers in the magnetosphere. Analysis of patterns of perturbations with corresponding whistler and lightning information from this period suggests that there were at least two distinct ionospheric disturbances in each hemisphere. Copyright 1990 by the American Geophysical Union.