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Published Papers 【 display / non-display 】

Published Papers 【 display / non-display 】

• Warm ocean accelerating tropical cyclone Hagibis (2019) through interaction with a mid-latitude westerly jet

  Ito Kosuke, Ichikawa Hana

  SOLA ( 公益社団法人 日本気象学会 )  17 ( 0 ) 1 - 6   2021 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

  　View Summary

  <p>One of the remarkable environmental characteristics of tropical cyclone (TC) Hagibis (2019) was the positive sea surface temperature (SST) anomaly observed in the western North Pacific Ocean. In this study, an ensemble-based sensitivity experiment was conducted with a nonhydrostatic model, focusing on the impact of SST on TC motion. The TC with the analyzed SST (warm run) moved faster near mainland Japan than with the lowered SST (cold run), as the TC in the warm run was embedded earlier in the mid-latitude westerly jet located to the north than that in the cold run. The TC displacement was consistent with the large decrease of geopotential height at 500-hPa (Z500) in the north of TC Hagibis during the warm run. Further investigation showed that the approach to the westerly jet presumably induced the low local inertial stability as well as the southwesterly vertical wind shear enhancing the upward mass flux in the north of the TC. They led the enhanced upper-tropospheric northward outflow from the TC energized by the warm SST, and it resulted in the decrease of the Z500 in the north. This study suggests that warm SST can affect TC tracks through interaction with mid-latitude westerly jets. </p>

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• Diurnal variation of the convective area and eye size associated with the rapid intensification of tropical cyclones

  LEE J.D.

  Monthly Weather Review ( Monthly Weather Review )  148 ( 10 ) 4061 - 4082   2020.10 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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• Recent Progress in the Fundamental Understanding of Tropical Cyclone Motion

  Kosuke ITO, Chun-Chieh WU, Kelvin T. F. CHAN, Ralf TOUMI, Chris DAVIS

  Journal of the Meteorological Society of Japan     2020 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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  While the fundamental understanding of the movement of a tropical cyclone (TC) is fairly mature, there are still notable advancements being made. This paper summarizes new concepts and updates on existing fundamental theories on TC movement obtained from simplified barotropic models, full-physics models, and data analysis particularly since 2014. It includes the recent works on the interaction of the TC with its environment and the fundamental aspects of predictability related to TC movement. The conventional concepts of the steering flow, β-gyre, and diabatic heating remain important. Yet, a more complete understanding of mechanisms governing TC movement serves as an important basis toward the further improvement of track forecasts.

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• Diurnal variation of the convective area and eye size associated with the rapid intensification of tropical cyclones

  Jae-Deok Lee, Chun-Chieh Wu, Kosuke Ito

  JOURNAL OF THE ATMOSPHERIC SCIENCES     2020 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

• Analyses of Extreme Precipitation Associated with the Kinugawa River Flood in September 2015 Using a Large Ensemble Downscaling Experiment

  Mikiko Fujita, Tomonori Sato, Tomohito J. Yamada, Sho Kawazoe, Masuo Nakano, Kosuke Ito

  Journal of the Meteorological Society of Japan   97 ( 2 ) 387 - 401   2019.04 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

  　View Summary

  We investigated extremely heavy precipitation that occurred around the Kinugawa River, Japan, in September 2015, and the probability of extreme precipitation occurrence, using data from a large ensemble forecast of more than 1,000 members that were dynamically downscaled to 1.6 km horizontal grid spacing. The observed event was statistically rare among simulated cases and the 3-day accumulated precipitation around the target area was equivalent to the 95th percentile among all simulated ensemble members. Our results show that this extreme precipitation event occurred under specific conditions: two coexisting typhoons at close proximity that produced a high atmospheric instability, and water vapor transported from the Pacific Ocean. We also assessed the probability of extreme precipitation in mountainous areas other than the Kinugawa River case. Heavy precipitation also occurred southwest of the Kinugawa River region due to two typhoons, similar to the Kinugawa River case. The tracks of these typhoons shifted marginally; however, there was a difference in the water vapor supplied to the area, causing heavy precipitation. The large-ensemble downscaled data used in this study hence enabled us to evaluate the occurrence probability of a torrential rainfall event that was rarely observed, which may contribute to updating a disaster-mitigating plan for possible similar disasters in future.

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• Achievements and future subjects of the 'Ultra-high Precision Mesoscale Weather Prediction' in SPIRE Field 3

  SAITO Kazuo, SEKO Hiromu, TSUYUKI Tadashi, NAKAMUARA Kozo, DUC Le, OIZUMI Tsutao, ITO Kosuke, KURODA Tohru, HASHIMOTO Akihiro, ITO Junshi, ORIGUCHI Seiji, KUNII Masaru, MASHIKO Wataru, YOKOTA Sho, KOBAYASHI Kenichiro, YAMASHIKI Yosuke, TSUBOKI Kazuhisa, CHEN Guixing

  日本地球惑星科学連合大会予稿集(Web)   2016   ROMBUNNO.AAS02‐07 (WEB ONLY)   2016

   

  J-GLOBAL

Academic Awards 【 display / non-display 】

Academic Awards 【 display / non-display 】

• Excellent paper award of the seismology society of Japan

  2012   The seismological society of Japan  

Grant-in-Aid for Scientific Research 【 display / non-display 】

Grant-in-Aid for Scientific Research 【 display / non-display 】

• Grant-in-Aid for Scientific Research(B)

  Project Year: 2018.04  -   

• Grant-in-Aid for challenging Exploratory Research

  Project Year: 2016.04  -  2018.03 

  Direct: 2,600,000 (YEN)  Overheads: 780,000 (YEN)  Total: 3,380,000 (YEN)

• Grant-in-Aid for Young Scientists(B)

  Project Year: 2014.04  -  2016.03 

  Direct: 1,500,000 (YEN)  Overheads: 450,000 (YEN)  Total: 1,950,000 (YEN)

• Grant-in-Aid for JSPS Fellows

  Project Year: 2009.04  -  2011.03