Could Narrow Bipolar Events Serve as a Distinct Lightning Proxy for Revealing Overshooting Thunderclouds Development?

Abstract Narrow bipolar events (NBEs) are often generated in overshooting thunderclouds (OT) penetrating the stratosphere. However, how and under what conditions OT produces such discharges remains unclear. With 3‐year lightning observations and simultaneous cloud top brightness temperature measurements over South China, we developed a more accurate OT detection algorithm to first investigate the effects of OT morphology and phase on NBEs genesis. The unprecedented data set of 6,646 OT cells and 117,518 NBEs are identified. Approximately 52% OTs are associated with NBEs and its occurrence increases with OT vertical depth but without obvious dependence on horizontal scale. The polarity of bursting NBEs is closely linked to OT phase. Positive NBEs outbursts prefer the transition phase from decaying to upwelling while negative polarity appears inhibited. Our results suggest ground‐based radio measurements of NBEs would serve as a new proxy to probe OT dynamics with implications for diagnosing coupling between the tropopause and lower stratosphere.