Characteristic Features of the Clouds Producing Thunderstorm Ground Enhancements
Ekaterina Svechnikova, Nikolay Ilin, E. A. Mareev, A. Chilingarian
Abstract
Abstract Thunderstorm ground enhancements (TGEs) are fluxes of energetic particles multiplied in thunderclouds, which may be registered by ground‐based detectors. Using the Weather Research and Forecasting (WRF) Model, the state of the atmosphere with a 1‐km horizontal resolution is modeled for convective events accompanied by TGEs observed at the high altitude Aragats Research Station in Armenia (40.47 N, 44.18 E, 3,200 m above sea level). By comparing the data obtained in observations with the results of simulations using a microphysical parameterization for WRF, a technique is developed for estimating charge distribution parameters. A typical charge distribution in a TGE‐producing cloud is found to be well approximated by a two‐layered charge structure with a lower positive charge region formed by graupel particles and an upper negative charge region formed by snow particles. The characteristic charge density is 0.01 nC/m 3 for the graupel cluster and −0.02 nC/m 3 for the snow cluster. A vertical distance of about 1–2 km between the lower positive and upper negative layers is sufficient for the development of an energetic particle avalanche.