著者

Yukie Moroda Kazuhisa Tsuboki Shinsuke Satoh Katsuhiro Nakagawa Tomoo Ushio Hiroshi Kikuchi

出版者

公益社団法人 日本気象学会

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.18, pp.110-115, 2022 (Released:2022-06-08)

参考文献数

16

被引用文献数

1

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A rapid rise of the lightning activity center in the upper part of a cloud is called a lightning bubble (LB). It remains unclear how LBs occur in thunderstorm clouds. Recently, high-spatiotemporal resolution data obtained by a phased array weather radar enabled observation of temporal changes in the three-dimensional structure of precipitation cores in a precipitation cell. To understand the mechanism by which LBs occur, we examined the relationship between the time-evolution of precipitation cores and the flash initiation points. After a precipitation core developed in an isolated thundercloud, the top height of the core reached its highest altitude and then started to descend. Meanwhile, the echo tops above the core continued to rise, which is termed an upward reflectivity pulse (URP). Over an hour, nine URPs were successively observed in the thundercloud. The average tracking period of the URPs was 3.9 minutes. Flash initiation points appeared near the highest points of the URPs and continued to rise with time. These observational results suggest that URPs cause LBs by enhancing the electric field, via the separation of graupel and ice crystals near the highest points of ascending URPs.

著者

Yukie Moroda Kazuhisa Tsuboki Shinsuke Satoh Katsuhiro Nakagawa Tomoo Ushio Hiroshi Kikuchi

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2022-018, (Released:2022-04-15)

被引用文献数

1

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A rapid rise of the lightning activity center in the upper part of a cloud is called a lightning bubble (LB). It remains unclear how LBs occur in thunderstorm clouds. Recently, high-spatiotemporal resolution data obtained by a phased array weather radar enabled observation of temporal changes in the three-dimensional structure of precipitation cores in a precipitation cell. To understand the mechanism by which LBs occur, we examined the relationship between the time-evolution of precipitation cores and the flash initiation points.After a precipitation core developed in an isolated thundercloud, the top height of the core reached its highest altitude and then started to descend. Meanwhile, the echo tops above the core continued to rise, which is termed an upward reflectivity pulse (URP). Over an hour, nine URPs were successively observed in the thundercloud. The average tracking period of the URPs was 3.9 minutes. Flash initiation points appeared near the highest points of the URPs and continued to rise with time. These observational results suggest that URPs cause LBs by enhancing the electric field, via the separation of graupel and ice crystals near the highest points of ascending URPs.

著者

Fusako Isoda Shinsuke Satoh Tomoo Ushio

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.14, pp.64-68, 2018 (Released:2018-06-23)

参考文献数

15

被引用文献数

2 6

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On 26 July 2012, localized rainfall from four isolated convective cells was observed by the Phased Array Weather Radar (PAWR) located in Osaka, Japan. The PAWR can observe fine three-dimensional features of precipitation every 30 seconds. In this paper, we investigated the evolution of localized isolated convective cells using the PAWR data. The first echoes appeared at around 5 km altitude, and light rain (25 dBZ) near the ground started in 3 to 5 minutes after the first echo. Heavy rain (50 dBZ) started in 9 to 15 minutes after the first echo. The lifespan of four convective cells was from 40 to 70 minutes.The reflectivity centroid over 25 dBZ (C25) of the first echo in developing stage descended first and then ascended within the several minutes. The behavior of the first echo motion looked complicated and it is difficult to be explained by the traditional conceptual model. In dissipation stage, the descending C25 was stopped by an alternation of precipitation core.

著者

Juan J. Ruiz Takemasa Miyoshi Shinsuke Satoh Tomoo Ushio

出版者

(公社)日本気象学会

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.11, pp.48-52, 2015 (Released:2015-04-28)

参考文献数

20

被引用文献数

3 8

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This study develops and tests a quality control (QC) algorithm for reflectivity from the single polarization phased array weather radar (PAWR) in Osaka, with particular focus on clutter detection, in preparation for radar data assimilation into a high resolution numerical model. The QC algorithm employs a Bayesian classification that combines the information from different parameters based on reflectivity and radial velocity. To take advantage of PAWR's unique high temporal and vertical resolutions, a new parameter based on the temporal variability of reflectivity is included. In addition, clutter probability estimations from previous volume scans are also included. The newly developed QC algorithm performs properly in two events characterized by heavy convective precipitation and stratiform precipitation.