Anomalously low negative cloud-to-ground lightning flash rates in intense convective storms observed during STERAO-A

Concurrent measurements from the CSU-CHILL multiparameter Doppler radar, th e Office National d'Etudes et de Recherches Aerospatiales VHF lightning int erferometer. and the National Lightning Detection Network, obtained during phase A of the Stratosphere-Troposphere Experiments: Radiation, Aerosols, O zone (STERAO-A) field project, provided a unique dataset with which to stud y the relationships between convective storm microphysics and associated Li ghtning. Two storms have been examined in detail in this study: 10 and 12 J uly 1996. Both storms were long lived, existing in some form for over 4 h a piece, and produced very low cloud-to-ground (CG) lightning flash rates, in particular negative CG flash rates (generally <1 min(-1) and often no CG h ashes for periods ranging from 10 to almost 30 min), during all or a portio n of their lifetimes while simultaneously producing relatively high intracl oud (IC) hash rates (>30 min(-1) at peak). For both storms, radar reflectiv ity intensity and the production of hail were anticorrelated with the produ ction of significant negative cloud-to-ground lightning. These observations are shown to be consistent with an elevated charge hypothesis and suggest a possible way of correlating updraft speed, hail, and storm severity to CG and IC flask rates.