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

摘要

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.