[A-AS04] Extreme Events and Mesoscale Weather: Observations and Modeling

[AAS04-07] Damaging Wind Event Observed by MRI Phased Array Weather Radar in the Summer of 2023

*足立 透¹、梅原 章仁¹ (1.気象研究所台風・災害気象研究部)

キーワード：フェーズドアレイレーダー、ダウンバースト、ガストフロント

In the summer of 2023, multiple severe damaging wind events occurred in the Kanto region. Japan Meteorological Agency (JMA) conducted damage surveys for ten events in Kanto, including Ibaraki, Saitama, Gunma, Tochigi, and Tokyo, from June to August. Seven out of ten events, which are likely downbursts or gust fronts with an estimated wind velocity of 25–50 m/s, occurred in the observation coverage of a phased array weather radar (PAWR) operated by Meteorological Research Institute (MRI) in Tsukuba, Ibaraki. Because the PAWR scans three-dimensional space within a range of 60 km every 30 seconds, we utilize the data to finely analyze the spatiotemporal structure of the parent storm system and the damaging wind. The seven events occurred in thermodynamically unstable conditions due to the daytime solar heating (and the higher-level cold airmass in some cases) and the moist air transported from the Pacific Ocean by the synoptic-scale wind field. Here, we focus on the event on August 1, which happened near the radar site at a distance of ~15 km. The PAWR data show a near-surface outflow pattern in an increased reflectivity area of the parent storm. The horizontal and vertical dimensions of the outflow were about 3–4 km and 200–300 m, respectively, suggesting the occurrence of a typical wet microburst. The PAWR data also show complex sub-kilometer scale enhanced wind velocity structures embedded in a larger wind structure. In the presentation, we will discuss the spatiotemporal structure of damaging wind events concerning the storm-scale behavior of their parent storm systems.
Acknowledgment: This work is supported by JSPS KAKENHI Grant JP21K03666.