- 著者
- Akihito Umehara Toru Adachi Wataru Mahiko Hiroshi Yamauchi
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.2021-034, (Released:2021-10-04)
- 被引用文献数
- 3
The tornadic debris signatures (TDSs) of the Ichihara Tornado associated with Typhoon Hagibis (2019) were observed using two operational C-band dual-polarimetric weather radars and an X-band phased-array weather radar (PAWR). This TDS observation was the first to be made over Japan in a typhoon environment. The TDS bins spread over time, and the maximum vertical and aerial extents reached 2.4 km and 9.41 km2, respectively. The estimated rise velocity of the TDS was 8 m s−1. The first TDS was detected ∼1 min before damage reporting began. The TDSs became clearer along with the rotational velocity of the near-surface vortex detected by PAWR. The copolar correlation coefficient reached a minimum (0.27) ∼1 min after the tornado passed the most severely damaged area and increased gradually over 4 min. This suggests that heavy and/or dense debris was lofted and immediately fell out and/or diffused, whereas light debris remained aloft for ≥ 4 min. By comparing the PAWR-detected vortex signatures with aerial photographs, we inferred that the first TDS comprised vegetated debris, the clearest TDS mainly comprised destroyed manmade structures. These results indicate that TDS detection is effective both for investigating damage and for recognizing tornado's occurrence even in a typhoon environment.
- 著者
- Hanako Y. Inoue Kenichi Kusunoki Toru Adachi Chusei Fujiwara Naoki Ishitsu Ken-ichiro Arai
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.15, pp.228-233, 2019 (Released:2019-11-12)
- 参考文献数
- 24
The characteristics and finescale evolution of misovortices within a snowband were examined using low-level high-resolution single- and dual-Doppler radar analysis. From 02:00 to 06:00 JST on 17 January 2017, many misovortices developed within three snowbands in the Japan Sea coastal region. The vortices developed along the shear line between the offshore north-northwesterly and the coastal northeasterly. As discussed in several previous studies of misovortices along airmass boundaries, horizontal shearing instability was considered to be a possible mechanism responsible for misovortex formation. A detailed investigation was performed on the most distinct snowband and misovortices embedded within it. Dual-Doppler analysis revealed a detailed behavior of vortex during merger, such as the morphological change from quasi-circular to elliptical shape, and the counterclockwise rotation which caused high-amplitude inflection of the shear line in less than 10 minutes. During the decay stage, the vortices weakened along with weakening convergence. The results suggest that evolution of the misovortex appears to have been closely tied to the low-level convergence within the vortex.
- 著者
- Hanako Y. Inoue Kenichi Kusunoki Toru Adachi Chusei Fujiwara Naoki Ishitsu Ken-ichiro Arai
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.2019-041, (Released:2019-10-18)
The characteristics and finescale evolution of misovortices within a snowband were examined using low-level high-resolution single- and dual-Doppler radar analysis. From 02:00 to 06:00 JST on 17 January 2017, many misovortices developed within three snowbands in the Japan Sea coastal region. The vortices developed along the shear line between the offshore north-northwesterly and the coastal northeasterly. As discussed in several previous studies of misovortices along airmass boundaries, horizontal shearing instability was considered to be a possible mechanism responsible for misovortex formation. A detailed investigation was performed on the most distinct snowband and misovortices embedded within it. Dual-Doppler analysis revealed a detailed behavior of vortex during merger, such as the morphological change from quasi-circular to elliptical shape, and the counterclockwise rotation which caused high-amplitude inflection of the shear line in less than 10 minutes. During the decay stage, the vortices weakened along with weakening convergence. The results suggest that evolution of the misovortex appears to have been closely tied to the low-level convergence within the vortex.
- 著者
- Akihito Umehara Toru Adachi Wataru Mashiko Hiroshi Yamauchi
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.17, pp.196-201, 2021 (Released:2021-11-25)
- 参考文献数
- 19
- 被引用文献数
- 3
The tornadic debris signatures (TDSs) of the Ichihara Tornado associated with Typhoon Hagibis (2019) were observed using two operational C-band dual-polarization weather radars and an X-band phased-array weather radar (PAWR). This TDS observation was the first to be made over Japan in a typhoon environment. The TDS bins spread over time, and the maximum vertical and aerial extents reached 2.4 km and 9.41 km2, respectively. The estimated rise velocity of the TDS was 8 m s−1. The first TDS was detected ∼1 min before damage reporting began. The TDSs became clearer along with the rotational velocity of the near-surface vortex detected by PAWR. The copolar correlation coefficient reached a minimum (0.27) ∼1 min after the tornado passed the most severely damaged area and increased gradually over 4 min. This suggests that heavy and/or dense debris was lofted and immediately fell out and/or diffused, whereas light debris remained aloft for ≥ 4 min. By comparing the PAWR-detected vortex signatures with aerial photographs, we inferred that the first TDS comprised vegetated debris, the clearest TDS mainly comprised destroyed manmade structures. These results indicate that TDS detection is effective both for investigating damage and for recognizing tornado's occurrence even in a typhoon environment.