The activity of cloud-to-ground flashes in a local thunderstorm

Vehicle-mounted X-band dual-polarization radar, located at coastal region (118.9 E, 25.1 N) in Fujian province, almost completely captured the entire life span of a local severe thunderstorm on August 28, 2009. Combine the radar strong echo volume and hydrometers retrieved by hydrometer identification (HID) algorithm, the characteristics of cloud-to-ground (CG) flash in different stage of thunderstorm were analyzed. The study case experienced several stages and developed into a squall line in its mature stage with a maximum CG rate of 85fl/5min. CGs mainly occurred in the convective region and CG rates per 5 minutes had a linear positive correlation with strong echo volume in convective region. Seven types hydrometers was identified by HID, and five types of dominant hydrometers were found in thunderstorm, they are rain, aggregates, low-density graupel, high-density graupel, and vertical ice. The spatial distribution of hydrometers showed that rain mainly located at lower portion of thunderstorm warmer than 0°C, high-density graupel at middle, low-density graupel and vertical ice at upper portion. CG rates were also positively correlated with the samples of dominant ice phase hydrometers in convective region.