THE BROAD OBJECTIVE OF THIS WORK WILL BE TO CONTINUE PROVIDING AN ASSESSMENT OF, AND INSIGHT INTO, THE NATURE AND IMPACT OF CHANGES IN THE PERFORMANCE OF THE US NATIONAL LIGHTNING DETECTION NETWORK (NLDN) DUE TO HARDWARE AND SOFTWARE UPGRADES, INCLUDING PRE?2003 NLDN DATA. IDENTIFICATION OF THESE CHANGES WILL FACILITATE INTERPRETATIONS OF THE NATURAL (I.E., NON?NETWORK RELATED) VARIATIONS IN CLOUD?TOGROUND LIGHTNING CHARACTERISTICS, AND HENCE WILL HELP ASSESS REAL CHANGES IN LIGHTNING NITROGEN OXIDES (LNOX) PRODUCTION, AN IMPORTANT TRACES GAS IN CLIMATE STUDIES. THESE EFFORTS WILL SUPPORT NATIONAL CLIMATE ASSESSMENT (NCA) STUDIES AT NASA/MSFC THAT INVOLVE EXAMINING THE INTER?RELATIONSHIPS BETWEEN LIGHTNING AND CLIMATE. DR. CUMMINS WILL ALSO CONTINUE TO EXAMINE CONUS PRECIPITATION ANOMALIES IN ORDER TO PROVIDE ADDITIONAL INSIGHT TO OTHER TEAM MEMBERS (VANT?HULL, CHRONIS, TIPPETT) WHO ARE CONDUCTING DRY LIGHTNING STUDIES AND ANALYSES OF THE ROMPS INDICATOR. FINALLY, CUMMINS WILL ASSESS IC:CG RATIO ESTIMATES OBTAINED BY KOSHAK (WHO OBTAINED THESE ESTIMATES BY COMPARING GEOSTATIONARY LIGHTNING MAPPER (GLM) DATA WITH NLDN DATA).