Tsutao Oizumi
Japan Agency for Marine-Earth Science and Technology
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Featured researches published by Tsutao Oizumi.
Theoretical and Applied Climatology | 2015
Kenichi Tatsumi; Tsutao Oizumi; Yosuke Yamashiki
In this study, we present a detailed analysis of the effect of changes in cloudiness (CLD) between a future period (2071–2099) and the base period (1961–1990) on daily minimum temperature (TMIN) and maximum temperature (TMAX) in the same period for the Shikoku region, Japan. This analysis was performed using climate data obtained with the use of the Statistical DownScaling Model (SDSM). We calibrated the SDSM using the National Center for Environmental Prediction (NCEP) reanalysis dataset for the SDSM input and daily time series of temperature and CLD from 10 surface data points (SDP) in Shikoku. Subsequently, we validated the SDSM outputs, specifically, TMIN, TMAX, and CLD, obtained with the use of the NCEP reanalysis dataset and general circulation model (GCM) data against the SDP. The GCM data used in the validation procedure were those from the Hadley Centre Coupled Model, version 3 (HadCM3) for the Special Report on Emission Scenarios (SRES) A2 and B2 scenarios and from the third generation Coupled Global Climate Model (CGCM3) for the SRES A2 and A1B scenarios. Finally, the validated SDSM was run to study the effect of future changes in CLD on TMIN and TMAX. Our analysis showed that (1) the negative linear fit between changes in TMAX and those in CLD was statistically significant in winter while the relationship between the two changes was not evident in summer, (2) the dependency of future changes in TMAX and TMIN on future changes in CLD were more evident in winter than in other seasons with the present SDSM, (3) the diurnal temperature range (DTR) decreased in the southern part of Shikoku in summer in all the SDSM projections while DTR increased in the northern part of Shikoku in the same season in these projections, (4) the dependencies of changes in DTR on changes in CLD were unclear in summer and winter. Results of the SDSM simulations performed for climate change scenarios such as those from this study contribute to local-scale agricultural and hydrological simulations and development of agricultural and hydrological models.
Scientific Reports | 2017
Junshi Ito; Tsutao Oizumi; Hiroshi Niino
Taking advantage of the huge computational power of a massive parallel supercomputer (K-supercomputer), this study conducts large eddy simulations of entire tropical cyclones by employing a numerical weather prediction model, and explores near-surface coherent structures. The maximum of the near-surface wind changes little from that simulated based on coarse-resolution runs. Three kinds of coherent structures appeared inside the boundary layer. The first is a Type-A roll, which is caused by an inflection-point instability of the radial flow and prevails outside the radius of maximum wind. The second is a Type-B roll that also appears to be caused by an inflection-point instability but of both radial and tangential winds. Its roll axis is almost orthogonal to the Type-A roll. The third is a Type-C roll, which occurs inside the radius of maximum wind and only near the surface. It transports horizontal momentum in an up-gradient sense and causes the largest gusts.
Stochastic Environmental Research and Risk Assessment | 2014
Kenichi Tatsumi; Tsutao Oizumi; Yosuke Yamashiki
Hydrological Research Letters | 2013
Kenichi Tatsumi; Tsutao Oizumi; Yosuke Yamashiki
Journal of The Meteorological Society of Japan | 2018
Tsutao Oizumi; Kazuo Saito; Junshi Ito; Thoru Kuroda; Le Duc
Japan Geoscience Union | 2018
Tsutao Oizumi; Kazuo Saito; Le Duc; Junshi Ito
Japan Geoscience Union | 2017
Tsutao Oizumi; Kazuo Saito; Junshi Ito; Le Duc
Japan Geoscience Union | 2017
Yosuke Yamashiki; Ryusuke Kuroki; Tsutao Oizumi
Japan Geoscience Union | 2017
Yosuke Yamashiki; Tsutao Oizumi; Ryusuke Kuroki
Japan Geoscience Union | 2016
Kazuo Saito; Hiromu Seko; Tadashi Tsuyuki; Kozo Nakamuara; Le Duc; Tsutao Oizumi; Kosuke Ito; Tohru Kuroda; Akihiro Hashimoto; Junshi Ito; Seiji Origuchi; Masaru Kunii; Wataru Mashiko; Sho Yokota; K. Kobayashi; Yosuke Yamashiki; Kazuhisa Tsuboki