Thunderstorm Electrification in STEPS-2000

New Mexico Institute Of Mining And Technology, Socorro NM

Investigators

Abstract

The Severe Thunderstorm Electrification and Precipitation Study field program (STEPS), planned for the early summer of 2000 in western Kansas, will provide a wide range of observations in and around thunderstorms using aircraft, radar, and other observing systems. As part of STEPS, an instrument will be flown on the T-28 storm-penetration aircraft that provides images of graupel and hail particles and simultaneously measures their electrical charges. Dr. Winn will maintain this instrument during the field program and collaborate in the analysis of the data afterwards. The data will be used to assess the so-called noninductive charging hypothesis of lightning generation, which attempts to explain the creation of strong electric fields in thunderstorms by the systematic transfer of charges between ice particles of different sizes as they collide. This project also includes the development and deployment during STEPS of a new, balloon-borne instrument for measuring vertical profiles of the electric field. Used in connection with the New Mexico Tech lightning-mapping array, its position is determined by GPS navigation and the data on electric field strength are transmitted to the array by a pulse-modulated signal. STEPS provides the opportunity to evaluate this instrument by comparing the measurements with those using conventional equipment. Analysis of the data will be coordinated with other NSF-supported STEPS projects, including the New Mexico Tech lightning mapper (ATM-9912073), the CHILL radar (ATM-9912051 and -9982030), and other balloon soundings of the electric field (ATM-9912562).