An Analysis of Lightning Characteristics during Hurricane Harvey

Hurricane Harvey made landfall near Corpus Christi, Texas, but produced heavy precipitation near the Houston region. Several explanations have been made to account for the destruction of Hurricane Harvey, including climate change and land use change associated with urbanization. Also importantly, Houston hosts one of the largest petrochemical complexes in the world. The concentration of fine particulate matter in this region frequently exceeds the annual average of the National Ambient Air Quality Standards (NAAQS), mainly because of emissions from the Houston industrial area. Numerical model simulations and ground-based measurements have shown that anthropogenic aerosols invigorate deep convection and enhance lightning near the Houston region. Understanding the influence of anthropogenic aerosols on tropical cyclones is necessary to accurately predict future storms with the hope of minimizing destruction in the industrialized Gulf region. Noticeably, there exist only a few measurable quantities that can be used to evaluate the effects of aerosols on convective systems, including precipitation, radar reflectivity, and lightning. In particular, the production of lightning is directly relevant to convection strength and the abundance of co-existing liquid and ice hydrometeors. This study was aimed at characterizing lightning during Hurricane Harvey and evaluating the hypothesis that industrial aerosols likely contributed to an increased lightning activity and overall intensity of the storm. In this study, ground-based measurements from the Houston Lightning Mapping Array (HLMA) and National Lightning Detection Network (NLDN) were used to determine the maximum horizontal dimensions of individual lightning flashes using the LMA display software, XLMA. The HLMA and NLDN data were also used to generate monthly and seasonal climatologies in the Houston area. In this presentation, the lightning flash density climatologies in the Houston region will be compared to the lightning activity during Hurricane Harvey. In addition, the characteristics of lightning dimensions during Hurricane Harvey will be discussed.