Introduction

The Los Alamos Sferic Array (LASA) is an array of electric field change meters operated as an experimental system for ground support of satellite observations of lightning. We now have a five year data set of over seven million multi-station, differential time-of-arrival located events. LASA was originally used primarily for ground-truthing the FORTE satellite observations of specific type of intracloud lightning activity called Narrow Bipolar Events (NBEs) or Compact Intracloud Discharges (CIDs) [Smith et al.(1999)]. The signature of CIDs observed in the VHF by FORTE were termed Trans-Ionospheric Pulse Pairs (TIPPs) [Massey et al.(1998)]. In support of GPS satellite observations of both CID and cloud-to-ground (CG) lightning, LASA's classification routines were expanded to identify both CIDs and CGs. Approximately half of all LASA events are identified as either CIDs or CGs. In order to improve event classification, we are beginning to algorithmically identify general intracloud lightning activity and improve our identification of CG lightning. This paper presents examples of intracloud lightning LF/VLF radiation observations in comparison to NBE, CG, and leader LF/VLF signatures.