Difference between lightning activities in thunderstorm cells with and without hailfall in western Tokyo

. Thunderstorm cells with heavy hailfall in Mitaka and Chofu on June 24, 2014, and in Koganei and Toshima on July 18, 2017, were investigated using data obtained from X-band multiparameter radar, ground-based atmospheric electric field, ground-based precipitation, and lightning location. For comparison, neighboring control cells with heavy rainfall but without hailfall were also investigated. The cells had a constant radius of approximately 10 km, and their centers were statistically obtained using the positions of positive and negative cloud-to-ground lightning (± CG). In both the target and control cells, the radar echo reflectivity, size, and updraft velocities after hailfall and heavy rainfall were similar, whereas the number of ± CG in the target cells was clearly smaller than that in the control ones. In contrast, the ice volume derived from the X-band multiparameter radar echo data in the target cells was greater than that in the control cells. Therefore, the large ice volume and the moderate number of ± CG were considered common features of cells experiencing hailfall.