Comparison Study of the Electrical Nature of Two Smoke‐Enhanced Sea Breeze Thunderstorm Cases During TRACER

Abstract

Sea breeze thunderstorm cases during the Tracking Aerosol Convection Interactions Experiment (TRACER) were analyzed in terms of lightning responses to aerosol influences. U.S. Department of Energy Atmospheric Radiation Measurement Mobile Facility (AMF), Houston Lightning Mapping Array (HLMA), and Earth Networks Total Lightning Network (ENTLN) measurements provided the primary aerosol and lightning data during TRACER. On 12 July 2022, sea breeze convection initiated near an active wildfire. The AMF S3 site (∼80 km northeast of the fire) measured a surface peak total aerosol number concentration of 184.8 cm−3 while ENTLN data revealed 18 strong positive cloud‐to‐ground (CG) lightning pulses (peak current ≥50 kA) when the convection was collocated with the smoke plume. No strong positive CG pulses were observed after the storm propagated away from the smoke plume. The 13 July 2022 case initiated near the same time and location in a post‐fire environment (∼83.6 cm−3) and the convection featured two strong positive CG pulses despite having a similar peak VHF source rate (∼41,000 (5 min)−1). The charge structure for both cases featured a normal tripole with a larger low‐level positive charge layer for the 13 July 2022 case. Three additional cases (6 July, 14 July, and 28 July 2022) were analyzed as controls. The 6 July and 28 July 2022 cases initiated within an urban environment while the 14 July 2022 case initiated in a rural aerosol regime and featured fewer strong positive CG pulses under weaker aerosol loading environments (<80 cm−3) with no smoke present.