Sprite Halos and Associated Lightning Characteristics over South America

As part of the Brazil Sprites II balloon campaign ground-based measurements were conducted from the Southern Space Observatory (SSO) near Santa Maria, Brazil (29.4 S, 53.8 W) during the summer 2006. Remarkably, over 580 transient luminous events (TLEs) were imaged from two large thunderstorms located over north-eastern Argentina on February 22-23 and March 3- 4 2006. The optical observations were made using two intensified CCD cameras arranged to view the low elevation sky with overlapping fields of view to capture the TLE information from the extensive storm systems. This poster focuses on the optical characteristics over 200 halos and sprite-halos with their associated polarity and charge moments as determined by an ELF-VLF lightning sensor also deployed at the SSO. The halo events from these two storms were overwhelmingly associated with positive lightning discharges, however at least 7 TLE's were associated with negative lightning strokes. In contrast, recent satellite measurements of halos over land-sea interfaces suggest that they are mainly associated with negative cloud-to-ground discharges. Coincident halo data with the World Wide Lightning Location Network (WWLLN) have also enabled a detailed investigation of the altitude and apparent optical diameters of the halos and sprite halos.