Dr. Tatsuya Yokota Profile

Dr. Tatsuya Yokota

Retired at National Institute for Environmental Studies

SPIE Involvement:

Author

Publications (36)

Proceedings Article | 19 November 2014 Paper

An update on GOSAT standard products at five-and-a-half years after the launch

Masataka Ajiro, Fumie Kawazoe, Tatsuya Yokota

Proceedings Volume 9264, 92640F (2014) https://doi.org/10.1117/12.2069387

KEYWORDS: Fourier transforms, Short wave infrared radiation, Carbon dioxide, Clouds, Data processing, Optical coherence tomography, Aerosols, Sensors, Laser induced breakdown spectroscopy, Standards development

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Proceedings Article | 20 October 2014 Paper

Development of PM2.5 density distribution visualization system using ground-level sensor network and Mie lidar

Hiroshi Okumura, Taiga Akaho, Yu Kojiro, Osamu Uchino, Isamu Morino, Tatsuya Yokota, Tomohiro Nagai, Tetsu Sakai, Takashi Maki, Akihiro Yamazaki, Kohei Arai

Proceedings Volume 9246, 92460V (2014) https://doi.org/10.1117/12.2067589

KEYWORDS: Atmospheric particles, LIDAR, Visualization, Earth's atmosphere, Sensor networks, Aerosols, Visual analytics, Motion analysis, Environmental sensing, Atmospheric sciences

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Proceedings Article | 17 October 2013 Paper

Retrievals of atmospheric CO2, CH4 and optical path modifications from the GOSAT observations

Andrey Bril, Sergey Oshchepkov, Tatsuya Yokota, Yukio Yoshida, Isamu Morino, Osamu Uchino, Dmitry Belikov, Shamil Maksyutov

Proceedings Volume 8890, 889008 (2013) https://doi.org/10.1117/12.2028486

KEYWORDS: Atmospheric optics, Carbon dioxide, Methane, Absorption, Satellites, Fourier transforms, Aerosols, Short wave infrared radiation, Atmospheric particles, Light scattering

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Proceedings Article | 4 February 2013 Paper

Improvement of web-based data acquisition and management system for GOSAT validation lidar data analysis

Hiroshi Okumura, Shoichiro Takubo, Takeru Kawasaki, Indra Nugraha Abdullah, Osamu Uchino, Isamu Morino, Tatsuya Yokota, Tomohiro Nagai, Tetsu Sakai, Takashi Maki, Kohei Arai

Proceedings Volume 8654, 86540X (2013) https://doi.org/10.1117/12.2003921

KEYWORDS: Data acquisition, LIDAR, Meteorology, Data modeling, Ozone, Atmospheric modeling, Data analysis, Cameras, Satellites, Magnetic resonance imaging

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Proceedings Article | 19 November 2012 Paper

Observation of aerosol parameters at Saga using GOSAT product validation lidar

Shoichiro Takubo, Hiroshi Okumura, Takeru Kawasaki, Indra Nugraha Abdullah, Osamu Uchino, Isamu Morino, Tatsuya Yokota, Tomohiro Nagai, Tetsu Sakai, Takashi Maki, Kohei Arai

Proceedings Volume 8526, 852613 (2012) https://doi.org/10.1117/12.977607

KEYWORDS: LIDAR, Aerosols, Backscatter, Data acquisition, Data modeling, Raman spectroscopy, Fourier transforms, Polarization, Molecules, Atmospheric particles

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Proceedings Article | 9 November 2012 Paper

GOSAT higher level products and the variation of retrieved XCO2 and XCH4

Hiroshi Watanabe, Akira Yuki, Fumie Kawazoe, Sayaka Kanekon, Masataka Ajiro, Tsuneo Matsunaga, Tatsuya Yokota

Proceedings Volume 8528, 85280Y (2012) https://doi.org/10.1117/12.977374

KEYWORDS: Fourier transforms, Short wave infrared radiation, Carbon dioxide, Clouds, Gases, Sensors, Aerosols, Environmental sensing, Satellites, Reflectivity

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Proceedings Article | 8 November 2012 Paper

Estimation of regional surface CO2 fluxes with GOSAT observations using two inverse modeling approaches

Shamil Maksyutov, Hiroshi Takagi, Dmitry Belikov, Tazu Saeki, Ruslan Zhuravlev, Alexander Ganshin, Alexander Lukyanov, Yukio Yoshida, Sergey Oshchepkov, Andrey Bril, Makoto Saito, Tomohiro Oda, Vinu Valsala, Ryu Saito, Robert Andres, Thomas Conway, Pieter Tans, Tatsuya Yokota

Proceedings Volume 8529, 85290G (2012) https://doi.org/10.1117/12.979664

KEYWORDS: Carbon dioxide, Atmospheric modeling, Data modeling, Carbon, Biological research, Ecosystems, Climatology, Combustion, Vegetation, Satellites

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Inverse estimation of surface C0₂ fluxes is performed with atmospheric transport model using ground-based and GOSAT observations. The NIES-retrieved C0₂ column mixing (X_c02) and column averaging kernel are provided by GOSAT Level 2 product v. 2.0 and PPDF-DOAS method. Monthly mean C0₂ fluxes for 64 regions are estimated together with a global mean offset between GOSAT data and ground-based data. We used the fixed-lag Kalman filter to infer monthly fluxes for 42 sub-continental terrestrial regions and 22 oceanic basins. We estimate fluxes and compare results obtained by two inverse modeling approaches. In basic approach adopted in GOSAT Level4 product v. 2.01, we use aggregation of the GOSAT observations into monthly mean over 5x5 degree grids, fluxes are estimated independently for each region, and NIES atmospheric transport model is used for forward simulation. In the alternative method, the model-observation misfit is estimated for each observation separately and fluxes are spatially correlated using EOF analysis of the simulated flux variability similar to geostatistical approach, while transport simulation is enhanced by coupling with a Lagrangian transport model Flexpart. Both methods use using the same set of prior fluxes and region maps. Daily net ecosystem exchange (NEE) is predicted by the Vegetation Integrative Simulator for Trace gases (VISIT) optimized to match seasonal cycle of the atmospheric C0₂ . Monthly ocean-atmosphere C0₂ fluxes are produced with an ocean pC02 data assimilation system. Biomass burning fluxes were provided by the Global Fire Emissions Database (GFED); and monthly fossil fuel C0₂ emissions are estimated with ODIAC inventory. The results of analyzing one year of the GOSAT data suggest that when both GOSAT and ground-based data are used together, fluxes in tropical and other remote regions with lower associated uncertainties are obtained than in the analysis using only ground-based data. With version 2.0 of L2 X_c02 the fluxes appear reasonable for many regions and seasons, however there is a need for improving the L2 bias correction, data filtering and the inverse modeling method to reduce estimated flux anomalies visible in some areas. We also observe that application of spatial flux correlations with EOF based approach reduces flux anomalies.

Proceedings Article | 8 November 2012 Paper

Web-based data acquisition and management system for GOSAT validation Lidar data analysis

Hiroshi Okumura, Shoichiro Takubo, Takeru Kawasaki, Indra Abdullah, Osamu Uchino, Isamu Morino, Tatsuya Yokota, Tomohiro Nagai, Tetsu Sakai, Takashi Maki, Kohei Arai

Proceedings Volume 8537, 853714 (2012) https://doi.org/10.1117/12.974892

KEYWORDS: Data acquisition, LIDAR, Meteorology, Cameras, Data analysis, Satellites, Ozone, Signal processing, Infrared imaging, Gases

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Proceedings Article | 3 October 2011 Paper

Update of the GOSAT higher level products 2.5 years after the launch

Hiroshi Watanabe, Akira Yuki, Kenji Hayashi, Fumie Kawazoe, Nobuyuki Kikuchi, Fumiho Takahashi, Tsuneo Matsunaga, Tatsuya Yokota

Proceedings Volume 8176, 81760I (2011) https://doi.org/10.1117/12.898391

KEYWORDS: Fourier transforms, Clouds, Short wave infrared radiation, Carbon dioxide, Data modeling, Data processing, Reflectivity, Aerosols, Atmospheric modeling, Satellites

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Proceedings Article | 4 November 2010 Paper

GOSAT higher level product status more than 1.5 years after the launch and planned improvement

Hiroshi Watanabe, Akira Yuki, Kenji Hayashi, Fumie Kawazoe, Nobuyuki Kikuchi, Fumiho Takahashi, Tsuneo Matsunaga, Tatsuya Yokota

Proceedings Volume 7862, 786205 (2010) https://doi.org/10.1117/12.871001

KEYWORDS: Fourier transforms, Carbon dioxide, Data processing, Short wave infrared radiation, Clouds, Aerosols, Data archive systems, Calibration, Data modeling, Gases

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Proceedings Article | 13 October 2010 Paper

GOSAT higher level product status 1.5 year after the launch

Hiroshi Watanabe, Akira Yuki, Kenji Hayashi, Fumie Kawazoe, Nobuyuki Kikuchi, Fumiho Takahashi, Tsuneo Matsunaga, Tatsuya Yokota

Proceedings Volume 7826, 782606 (2010) https://doi.org/10.1117/12.865577

KEYWORDS: Fourier transforms, Data processing, Short wave infrared radiation, Clouds, Carbon dioxide, Aerosols, Data archive systems, Data modeling, Satellites, Calibration

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Proceedings Article | 23 September 2009 Paper

Current status of GOSAT higher level products by NIES GOSAT DHF

Hiroshi Watanabe, Hironari Ishihara, Kenji Hayashi, Fumie Kawazoe, Nobuyuki Kikuchi, Tatsuya Yokota

Proceedings Volume 7474, 74740L (2009) https://doi.org/10.1117/12.831246

KEYWORDS: Fourier transforms, Clouds, Calibration, Short wave infrared radiation, Carbon dioxide, Sun, Aerosols, Data acquisition, Sensors, Picosecond phenomena

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Proceedings Article | 13 October 2008 Paper

Correction of atmospheric scattering effects in space-based observations of methane and carbon dioxide: model study for synthesized GOSAT spectra

Andrey Bril, Sergey Oshchepkov, Tatsuya Yokota

Proceedings Volume 7107, 71070U (2008) https://doi.org/10.1117/12.799712

KEYWORDS: Atmospheric modeling, Methane, Carbon dioxide, Atmospheric corrections, Scattering, Algorithm development, Atmospheric optics, Clouds, Atmospheric particles, Aerosols

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Proceedings Article | 9 October 2008 Paper

Airborne SWIR FTS for GOSAT validation and calibration

Hiroshi Suto, Akihiko Kuze, Masakatsu Nakajima, Takashi Hamazaki, Tatsuya Yokota, Gen Inoue

Proceedings Volume 7106, 71060M (2008) https://doi.org/10.1117/12.799963

KEYWORDS: Fourier transforms, Short wave infrared radiation, Signal to noise ratio, Polarization, Sensors, Atmospheric modeling, CCD image sensors, Charge-coupled devices, Calibration, Modulation

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Proceedings Article | 9 October 2008 Paper

Detailed design of the GOSAT DHF at NIES and data acquisition/processing/distribution strategy

Hiroshi Watanabe, Hironari Ishihara, Kenji Hayashi, Fumie Kawazoe, Nobuyuki Kikuchi, Nawo Eguchi, Tsuneo Matsunaga, Tatsuya Yokota

Proceedings Volume 7106, 71060N (2008) https://doi.org/10.1117/12.801238

KEYWORDS: Fourier transforms, Sun, Aerosols, Data modeling, Clouds, Atmospheric modeling, Carbon dioxide, Data acquisition, Satellites, Gases

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GOSAT Project (GOSAT stands for Greenhouse gases Observation SATellite) is a joint project of MOE (Ministry of the Environment), JAXA (Japan Aerospace Exploration Agency) and NIES (National Institute for Environmental Studies (NIES). Data acquired by TANSO-FTS (Fourier Transform Spectrometer) and TANSO-CAI (Cloud and Aerosol Imager) on GOSAT (TANSO stands for Thermal And Near infrared Sensor for carbon Observation) will be collected at Tsukuba Space Center @ JAXA. The level 1A and 1B data of FTS (interferogram and spectra, respectively) and the level 1A of CAI (uncorrected data) will be generated at JAXA and will be transferred to GOSAT Data Handling facility (DHF) at NIES for further processing. Radiometric and geometric correction will be applied to CAI L1A data to generate CAI L1B data. From CAI L1B data, cloud coverage and aerosol information (CAI Level 2 data) will be estimated. The FTS data that is recognized to have "low cloud coverage" by CAI will be processed to generate column concentration of carbon dioxide CO₂ and methane CH₄ (FTS Level 2 data). Level 3 data will be "global map column concentration" of green house gases averaged in time and space. Level 4 data will be global distribution of carbon source/sink model and re-calculated forward model estimated by inverse model. Major data flow will be also described. The Critical Design Review (CDR) of the DHF was completed in early July of 2007 to prepare the scheduled launch of GOSAT in early 2009. In this manuscript, major changes after the CDR are discussed. In addition, data acquisition scenario by FTS is also discussed. The data products can be searched and will be open to the public through GOSAT DHF after the data validation process. Data acquisition plan is also discussed and the discussion will cover lattice point observation for land area, and sun glint observation over water area. The Principal Investigators who submitted a proposal for Research Announcement will have a chance to request the specific observation, early standard data delivery and research data delivery.

Proceedings Article | 26 October 2007 Paper

Disturbances and their corrections in space observation with GOSAT Fourier transform spectrometer

Tadao Aoki, Tatsuya Yokota, Gen Inoue, Koji Nobuta, Akira Kotani

Proceedings Volume 6748, 674812 (2007) https://doi.org/10.1117/12.736793

KEYWORDS: Fourier transforms, Satellites, Doppler effect, Carbon monoxide, Mirrors, Gases, Transmittance, Spectroscopy, Sensors, Reflection

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Proceedings Article | 17 October 2007 Paper

Development of GOSAT ground data system at NIES and the data processing strategy

Hiroshi Watanabe, Hironari Ishihara, Keiichiro Ninomiya, Kaduo Hiraki, Tsuneo Matsunaga, Tatsuya Yokota

Proceedings Volume 6744, 67440H (2007) https://doi.org/10.1117/12.740705

KEYWORDS: Fourier transforms, Data modeling, Data centers, Data storage, Clouds, Data processing, Atmospheric modeling, Short wave infrared radiation, Aerosols, Data acquisition

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Proceedings Article | 17 October 2007 Paper

Carbon dioxide retrieval from reflected sunlight spectra in the presence of cirrus cloud: model studies

Andrey Bril, Sergey Oshchepkov, Tatsuya Yokota

Proceedings Volume 6745, 674502 (2007) https://doi.org/10.1117/12.737233

KEYWORDS: Clouds, Carbon monoxide, Carbon dioxide, Atmospheric modeling, Satellites, Data modeling, Gases, Oxygen, Atmospheric optics, Short wave infrared radiation

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Proceedings Article | 26 September 2007 Paper

Development of airborne SWIR FTS for GOSAT validation and calibration

Hiroshi Suto, Akihiko Kuze, Yutaka Kaneko, Takashi Hamazaki, Isamu Morino, Hiroyuki Oguma, Tatsuya Yokota, Gen Inoue

Proceedings Volume 6678, 667816 (2007) https://doi.org/10.1117/12.733194

KEYWORDS: Fourier transforms, Signal to noise ratio, Short wave infrared radiation, Modulation, Atmospheric modeling, Sensors, Calibration, Satellites, Infrared radiation, CCD cameras

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Proceedings Article | 22 December 2006 Paper

Information and disturbances contained in the reflected solar radiation spectra measured with space-borne Fourier transform spectrometer for greenhouse gas mapping

Tadao Aoki, Tatsuya Yokota, Gen Inoue, Koji Nobuta, Akira Kotani

Proceedings Volume 6405, 640506 (2006) https://doi.org/10.1117/12.693840

KEYWORDS: Fourier transforms, Satellites, Carbon monoxide, Gases, Mirrors, Spectral resolution, Reflection, Solar radiation, Spectroscopy, Absorption

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Proceedings Article | 22 December 2006 Paper

Application of the equivalence theorem to simulate GOSAT observation data under cirrus-present condition

Sergey Oshchepkov, Andrey Bril, Tatsuya Yokota, Gen Inoue

Proceedings Volume 6405, 640509 (2006) https://doi.org/10.1117/12.693537

KEYWORDS: Clouds, Aerosols, Monte Carlo methods, Transmittance, Atmospheric modeling, Atmospheric particles, Scattering, Photon transport, Rayleigh scattering, Absorption

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Proceedings Article | 30 December 2004 Paper

A comparative study of stratospheric temperatures between ILAS-II and other data

Takafumi Sugita, Tatsuya Yokota, Hideaki Nakajima, Hirokazu Kobayashi, Naoko Saitoh, Hiroyuki Kawasaki, Masatoshi Usami, Hisaya Saeki, Mariko Horikawa, Yasuhiro Sasano

Proceedings Volume 5652, (2004) https://doi.org/10.1117/12.570872

KEYWORDS: Spectroscopy, Temperature metrology, Satellites, Sensors, Absorption, Earth's atmosphere, Error analysis, Visible radiation, Transmittance, Spectral resolution

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Proceedings Article | 30 December 2004 Paper

Test measurements by a BBM of the nadir-looking SWIR FTS aboard GOSAT to monitor CO2 column density from space

Tatsuya Yokota, Hiroyuki Oguma, Isamu Morino, Akiko Higurashi, Tadao Aoki, Gen Inoue

Proceedings Volume 5652, (2004) https://doi.org/10.1117/12.578497

KEYWORDS: Carbon monoxide, Short wave infrared radiation, Fourier transforms, Data modeling, Atmospheric modeling, Satellites, Sensors, Gases, In situ metrology, Algorithm development

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Proceedings Article | 30 November 2004 Paper

Atmospheric environment monitoring by the ILAS-II onboard the ADEOS-II satellite

Hideaki Nakajima, Takafumi Sugita, Tatsuya Yokota, Yasuhiro Sasano

Proceedings Volume 5571, (2004) https://doi.org/10.1117/12.568048

KEYWORDS: Spectrometers, Sensors, Ozone, Signal to noise ratio, Sun, Satellites, Infrared radiation, Data acquisition, Earth's atmosphere, Atmospheric monitoring

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Proceedings Article | 2 February 2004 Paper

Current status and early results of the ILAS-II onboard the ADEOS-II Satellite

Hideaki Nakajima, Takafumi Sugita, Tatsuya Yokota, Yasuhiro Sasano

Proceedings Volume 5234, (2004) https://doi.org/10.1117/12.510022

KEYWORDS: Spectrometers, Sensors, Sun, Satellites, Infrared radiation, Ozone, Signal to noise ratio, Infrared spectroscopy, Visible radiation, Aerosols

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Proceedings Article | 18 December 2002 Paper

Introduction of SOFIS/FTS calibration system

Takahiro Kawashima, Shigetaka Mori, Jun Tanii, Yasuhiro Sasano, Hideaki Nakajima, Tatsuya Yokota, Takafumi Sugita, Akihiko Kuze, Katsunori Waragai

Proceedings Volume 4818, (2002) https://doi.org/10.1117/12.451369

KEYWORDS: Sensors, Fourier transforms, Spectroscopy, Calibration, Sun, Visible radiation, Satellites, Spectral resolution, Semiconductor lasers, Modulation

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Proceedings Article | 31 January 2002 Paper

Simplified method for measuring minor gas constituents from ILAS-II transmittance spectra

Hiroshi Hanaizumi, Tatsuya Yokota

Proceedings Volume 4539, (2002) https://doi.org/10.1117/12.454428

KEYWORDS: Transmittance, Gases, Atmospheric modeling, Data modeling, Sensors, Radiative transfer, Temperature metrology, Numerical simulations, Error analysis, Absorption

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In order to measure vertical profiles of minor gas concentrations in the stratosphere, Improved Limb Atmosphere Spectrometers (ILAS and ILAS-II) have been developed. ILAS was the first generation sensor and made observations in 1996 and 1997. ILAS-II will measure atmospheric limb transmittance in 66 spectral bands (whereas 44 for ILAS) in the thermal infrared region by observing solar ray passed through the atmosphere. Vertical profiles of minor gases are simultaneously retrieved by a spectral fitting algorithm with an onion-peeling method for vertical profiling. This algorithm adopts a precise radiative transfer calculation and is very accurate, but usually the standard radiative transfer calculation needs huge volume of line-by-line calculations of molecular absorption to simulate theoretical limb transmittance spectra by using the HITRAN database. Methods for accelerating the algorithm have been required. In the ILAS operational program, a table look-up method, which needs an excellent computer system, was used for rapid calculations. We proposed a simplified method, which predicts the gas profiles from the measured limb transmittance spectra and vertical profiles of atmospheric pressure and temperature without iterative calculations by using a multiple regression technique. The Principal Component Expansion (PCE) is used for reducing the scale of the multiple regression model. In the training process, coefficients of the model are estimated from the previously retrieved data sets including measured limb transmittance spectra, vertical profiles of atmospheric pressure and temperature, and retrieved gas profiles. Then, the method predicts gas profiles from the newly measured limb transmittance spectra and pressure and temperature profiles. The validity of the method was confirmed by numerical simulation using the MODTRAN v.3.5 radiative transfer code. The proposed method was also applied to the actual 3474 ILAS observation data sets. The model trained by 3373 data sets well predicted the gas profiles for another 100 data sets which are selected randomly . This proposed method can be used for quick look of ILAS-II measured data and for generating the initial profiles for the operational spectral fitting algorithm.