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2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS), 2014
A winter thunderstorm was observed in the Shonai area in the northern part of Japan on 30 Novembe... more A winter thunderstorm was observed in the Shonai area in the northern part of Japan on 30 November 2010. Data from three-dimensional lightning mapping system and two X-band Doppler radars were used to analyze the spatial-temporal relationship between winter lightning channel, reflectivity core, and airflow structure in the thunderclouds. A lightning leader propagating from a rim of echo region to the echo region with high reflectivity involving large vertical vorticity was visualized in 3D. This result indicates that strong updraft caused by airflow convergence in the precipitation system contributed to accumulate positive charges around-10°C level and enhance vertical vorticity by stretching on the convergence line.
SOLA, 2015
Cloud-to-ground (CG) and total (both CG and intracloud) lightning trends were investigated in a t... more Cloud-to-ground (CG) and total (both CG and intracloud) lightning trends were investigated in a tornado-producing (F2) supercell thunderstorm that occurred over the Kanto Plain in Japan on 2 September 2013. The spatiotemporal signatures of mesocyclone (MC) and storm development were also analyzed using Doppler radar data. The results revealed that rapid increases of lightning flash rates ("lightning jumps") occurred in CG and total flash rates 0−7 and 0−14 min before tornadogenesis, respectively, which are similar to those observed in the United States. However, the CG polarity change reported in previous studies was not observed, i.e., 96% of CG flashes were negative. The vertical vorticity of the MC was larger in the mid-level (4−6 km) than the low level (2 km) at the beginning stage of the lightning jumps, which might have led to updraft enhancement above the freezing level appropriate for the rapid increases in lightning flash rates.
IEEJ Transactions on Fundamentals and Materials, 2014
2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS), 2014
A winter thunderstorm was observed in the Shonai area in the northern part of Japan on 30 Novembe... more A winter thunderstorm was observed in the Shonai area in the northern part of Japan on 30 November 2010. Data from three-dimensional lightning mapping system and two X-band Doppler radars were used to analyze the spatial-temporal relationship between winter lightning channel, reflectivity core, and airflow structure in the thunderclouds. A lightning leader propagating from a rim of echo region to the echo region with high reflectivity involving large vertical vorticity was visualized in 3D. This result indicates that strong updraft caused by airflow convergence in the precipitation system contributed to accumulate positive charges around-10°C level and enhance vertical vorticity by stretching on the convergence line.
SOLA, 2015
Cloud-to-ground (CG) and total (both CG and intracloud) lightning trends were investigated in a t... more Cloud-to-ground (CG) and total (both CG and intracloud) lightning trends were investigated in a tornado-producing (F2) supercell thunderstorm that occurred over the Kanto Plain in Japan on 2 September 2013. The spatiotemporal signatures of mesocyclone (MC) and storm development were also analyzed using Doppler radar data. The results revealed that rapid increases of lightning flash rates ("lightning jumps") occurred in CG and total flash rates 0−7 and 0−14 min before tornadogenesis, respectively, which are similar to those observed in the United States. However, the CG polarity change reported in previous studies was not observed, i.e., 96% of CG flashes were negative. The vertical vorticity of the MC was larger in the mid-level (4−6 km) than the low level (2 km) at the beginning stage of the lightning jumps, which might have led to updraft enhancement above the freezing level appropriate for the rapid increases in lightning flash rates.
IEEJ Transactions on Fundamentals and Materials, 2014