Prof. Toshiki Iwasaki Profile

Prof. Toshiki Iwasaki

Professor at Tohoku Univ

SPIE Involvement:

Author

Proceedings Article | 21 December 2024 Paper

Feasibility study of space-based Doppler wind Lidar for global wind profiling

Shoken Ishii, Kozo Okamoto, Hajime Okamoto, Toshiyoshi Kimura, Takuji Kubota, Daisuke Sakaizawa, Koichi Fujihira, Izumi Okabe, Tsuyoshi Sekiyama, Ayako Matsumoto, Yoshiaki Miyamoto, Tetsuya Takemi, Tomoaki Nishizawa, Atsushi Sato, Riko Oki, Masaki Satoh, Toshiki Iwasaki

Proceedings Volume 13265, 132650A (2024) https://doi.org/10.1117/12.3040281

KEYWORDS: Profiling, LIDAR, Doppler effect, Wind measurement, Meteorology, Meteorological satellites, Vegetation, Temporal resolution, Satellites, Remote sensing

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Proceedings Article | 8 November 2012 Paper

Future Doppler lidar wind measurement from space in Japan

S. Ishii, T. Iwasaki, M. Sato, R. Oki, K. Okamoto, T. Ishibashi, P. Baron, T. Nishizawa

Proceedings Volume 8529, 85290A (2012) https://doi.org/10.1117/12.977283

KEYWORDS: LIDAR, Doppler effect, Wind measurement, Space telescopes, Telescopes, Atmospheric particles, Atmospheric modeling, 3D modeling, Aerosols, Data modeling

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Proceedings Article | 12 December 2006 Paper

Coherent Doppler lidar observation and numerical simulation of gap wind Kiyokawa-dashi in Japan

K. Sasaki, S. Ishii, K. Mizutani, H. Kanno, D. Matsushima, W. Sha, T. Iwasaki

Proceedings Volume 6409, 64090H (2006) https://doi.org/10.1117/12.697843

KEYWORDS: Numerical simulations, LIDAR, Doppler effect, Atmospheric modeling, Computer simulations, 3D modeling, Communication and information technologies, Environmental sensing, Transmitters, Sensors

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Proceedings Article | 8 December 2006 Paper

Relationships amongs the Indian monsoon, the South China Sea monsoon, and the Western North Pacific precipitation

Rosbintarti Kartika Lestari, Yuichiro Umekawa, Toshiki Iwasaki

Proceedings Volume 6404, 64040U (2006) https://doi.org/10.1117/12.693771

KEYWORDS: Convection, Positive feedback, Atmospheric modeling, Compound parabolic concentrators, Remote sensing, Atmospheric sensing, Electroluminescence, Lanthanum, Spectral models, Data analysis

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It is hypothesized that the South China Sea (SCS) monsoon and the Indian monsoon intensify each other in the boreal summer. The Indian monsoon westerlies strengthen the SCS monsoon through the WE (Wind- Evaporation feedback) mechanism, but weaken it through the reduction in SCS SST. The SCS monsoon may have a positive feedback to enhance the Indian monsoon westerlies through the Walker circulation. Further question is how the convective activity over the Western North Pacific (WNP) interacts the Indian monsoon westerlies. The WNP SST may affect the Indian monsoon through the WNP precipitation. In this study, we investigate the relationships among the Indian monsoon, SCS monsoon and WNP activities from various observational data. The regression coefficient analyses are made. The data are NCEP reanalysis data, the CMAP precipitation data and ICOADS SST data averaging over June-July-August (JJA) for 21 years (1982-2002). First, the precipitation anomalies are regressed to the Indian monsoon westerly anomaly. The result shows that the Indian monsoon westerlies are positively correlated with the SCS precipitation. It indicates that the surface heating exchange over the SCS region is largely induced by the Indian monsoon westerlies and/or the SCS monsoon enhances the Indian monsoon westerlies. Another map of the regression of the 850hPa wind field anomalies to the WNP precipitation anomaly also shows that the Indian monsoon westerlies are positively correlated with the WNP precipitation. Completing this result, we confirm that the WNP precipitation and WNP SST have a positive correlation. Thus, the strengthening of the Indian monsoon westerlies and SCS westerlies may be also induced by the precipitation increase on the WNP region through the stronger east-west circulation associated with the warmer WNP SST. From the above results, it is found that the Indian monsoon westerlies are strongly correlated with the SCS monsoon activity and the WNP precipitation. Probably, the SCS monsoon is affected by the Indian monsoon through the WE, and affects the Indian monsoon through the diabatic heating. Further link is found to the precipitation over the WNP. To confirm the mechanism of correlation, the model study is underway.

Proceedings Article | 14 April 2003 Paper

Analysis of secondary circulation of the polar vortex

Toshiki Iwasaki, Daisuke Tanaka, Sakiko Shimizuguchi

Proceedings Volume 4899, (2003) https://doi.org/10.1117/12.466356

KEYWORDS: Thermodynamics, Satellites, Stratosphere, Diagnostics, Transmission electron microscopy, Earth observing sensors, Climatology, Data analysis, Halogens, Spectroscopy

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Proceedings Article | 13 February 2001 Paper

Estimation of orbital Doppler shift change due to nutation of attitude for 2-um coherent Doppler lidar on ISS-JEM (International Space Station-Japanese Experimental Module)

Makoto Totsuka, Kazuhiro Asai, Toshiki Iwasaki, Kohei Mizutani, Toshikasu Itabe

Proceedings Volume 4153, (2001) https://doi.org/10.1117/12.417073

KEYWORDS: Doppler effect, LIDAR, Wind measurement, Error analysis, 3D metrology, Velocity measurements, Troposphere, Atmospheric sciences, Continuous wave operation, Motion measurement

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