Properties Of Negative Initial Leaders And Flash Size In A Cluster Of Supercells

The data is associated with the paper titled "Properties of negative initial leaders and flash size in a cluster of supercells" . The abstract is as follows: Properties of negative initial leaders (NILs) and flash size in a cluster of supercells with generally inverted charge structure in Oklahoma on 10−11 May 2010 are examined, primarily using Lightning Mapping Array data. A method to identify NILs from large data sets is proposed. Median values of 18.00 ms, 1.02 km, 0.65 × 10⁵ m s⁻¹, and 47.24° are found for NIL duration, three-dimensional (3D) displacement, 3D displacement speed, and the angle between the displacement and the vertical directions, respectively. Median NIL speeds initially decrease with increasing height, but begin increasing above 12 km, possibly related to the rapid reduction in air density. The NILs decelerate during the early stage, particularly during the first 6 ms. The NILs in small-size charge regions tend to have low speeds, vice versa. The flash duration, horizontal distance, vertical distance, flash area and flash volume have median values of 0.27 s, 5.54 km, 3.67 km, 9.67 km², and 14.37 km³, respectively. All parameters follow lognormal distributions. Most flashes (83.18%) extend primarily in the horizontal direction. Flash area shows an inverse relationship with flash initiation density (FID) at high frequency during storm evolution. Although large FIDs generally occur in regions with small flash sizes, the smallest flash size is not collocated with large FID value. Flash duration changes independently of flash area in regions with large FID. A hypothesis is proposed to explain the observations in this study and previous studies on the correlations among convection, flash activity, flash size, and flash duration.