著者

IKUTA Yasutaka FUJITA Tadashi OTA Yukinari HONDA Yuki

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2021-076, (Released:2021-09-14)

被引用文献数

11

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The regional data assimilation system at the Japan Meteorological Agency employs a variational data assimilation system on the basis of the non-hydrostatic model ASUCA (named ASUCA-Var). This paper reviews configurations and the current status of ASUCA-Var. To consider the consistency of analysis and prognostic variables, the control variables of ASUCA-Var include soil variables and basic atmospheric variables. The background-errors based on the control variables are calculated every three hours for land and sea grid points to better reflect the representative error covariance structure, taking into account daily variations and differences in structure on land and sea. Although the cost function is designed to be a perfect quadratic form, the basic field update method in the optimization process allows the nonlinearity of the observation operator and numerical weather prediction model to be incorporated into the solution of optimization problem in the incremental four-dimensional variational (4D-Var) method. The outer/inner models used in the incremental 4D-Var method are based on ASUCA, with suitable configurations according to each resolution and applied linearization. Observation operators are implemented for various kinds of observations used, with unified interfaces encapsulating external simulators. Variational quality control and variational bias correction are also introduced for advanced observation handling within the variational system. Parallelization is introduced to enhance computational efficiency, including adjoint calculations. To assess the impact of assimilated observations, degrees of freedom for signal are also available. In addition, as a system for operational use, ASUCA-Var is designed for sustainable development. The meso-scale analysis and local analysis workflows are presented as operational implementations of ASUCA-Var. ASUCA-Var improves forecasting in a wide range of validation indices. The major future improvements of ASUCA-Var include the introduction of the flow-dependent background-error and the extension of the control variable to hydrometeors, which are expected to enhance the prediction accuracy of the operational regional model.

著者

板倉 嘉哉 本田 祐基 Itakura Yoshiya Honda Yuki

出版者

宇宙航空研究開発機構

雑誌

宇宙航空研究開発機構特別資料: 第41回流体力学講演会/航空宇宙数値シミュレーション技術シンポジウム2009論文集 = JAXA Special Publication: Proceedings fo 41st Fluid Dynamics Conference / Aerospace Numerical Simulation Symposium 2009 (ISSN:1349113X)

巻号頁・発行日

vol.JAXA-SP-09-011, 2010-02-26

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平成21年6月18-19日. 宇宙航空研究開発機構調布航空宇宙センター

著者

本田 由紀 Honda Yuki

出版者

法政大学大原社会問題研究所

雑誌

大原社会問題研究所雑誌 (ISSN:09129421)

巻号頁・発行日

no.654, pp.26-35, 2013-04

著者

Honda Yuki Maret Elizabeth Hirano Atsushi Tanaka Takeshi Makino Kotaro Hase Muneaki

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.102, no.22, pp.222109, 2013-06

被引用文献数

1

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We have used a femtosecond pump-probe impulsive Raman technique to explore the polarization dependence of coherent optical phonons in highly purified and aligned semiconducting single-wall carbon nanotubes (SWCNTs). Coherent phonon spectra for the radial breathing modes (RBMs) exhibit a different monochromatic frequency between the film and solution samples, indicating the presence of differing exciton excitation processes. By varying the polarization of the incident pump beam on the aligned SWCNT film, we found that the anisotropy of the coherent RBM excitation depends on the laser wavelength, which we consider to be associated with the resonant and off-resonant behavior of RBM excitation.