Dr. Riko Oki Profile

Dr. Riko Oki

Associate Senior Researcher at Japan Aerospace Exploration Agency

SPIE Involvement:

Conference Program Committee | Author

Publications (24)

Proceedings Article | 30 October 2018 Paper

Current status of the Dual-frequency precipitation Radar on the Global Precipitation Measurement core spacecraft and scan pattern change test operations results

Kinji Furukawa, Kosuke Yamamoto, Takuji Kubota, Riko Oki, Toshio Iguchi

Proceedings Volume 10776, 1077602 (2018) https://doi.org/10.1117/12.2323964

KEYWORDS: Radar, Space operations, Calibration, Satellites, Aerospace engineering, Communication and information technologies, Observatories, Microwave radiation, Radiometry, Ku band

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Proceedings Article | 23 October 2018 Paper

Drop size distribution observed by dual-frequency precipitation radar onboard global precipitation measurement core satellite

Moeka Yamaji, Takuji Kubota, Hiroshi Takahashi, Atsushi Hamada, Yukari Takayabu, Riko Oki

Proceedings Volume 10782, 107820H (2018) https://doi.org/10.1117/12.2324640

KEYWORDS: Radar, Satellites, Statistical analysis, Earth observing sensors, Particles

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Proceedings Article | 22 October 2018 Paper

Impact study on the accuracy of Global Satellite Mapping of Precipitation (GSMaP) caused by future small precipitation radar constellation

Moeka Yamaji, Takuji Kubota, Riko Oki

Proceedings Volume 10776, 1077614 (2018) https://doi.org/10.1117/12.2323967

KEYWORDS: Radar, Satellites, Meteorology

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Proceedings Article | 25 September 2018 Presentation + Paper

Analysis of the GPM/DPR wide swath experiment assuming future spaceborne precipitation radar

Kosuke Yamamoto, Kinji Furukawa, Nobuhiro Takahashi, Takuji Kubota, Riko Oki, Kaya Kanemaru

Proceedings Volume 10785, 107850O (2018) https://doi.org/10.1117/12.2325273

KEYWORDS: Radar, Satellites, Aerospace engineering, Statistical analysis, Antennas, Environmental sensing

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Proceedings Article | 29 September 2017 Presentation + Paper

Prime mission results of the dual-frequency precipitation radar on the global precipitation measurement core spacecraft and the version 5 GPM standard products

K. Furukawa, T. Nio, R. Oki, T. Kubota, T. Iguchi

Proceedings Volume 10423, 104230N (2017) https://doi.org/10.1117/12.2276765

KEYWORDS: Radar, Satellites, Microwave radiation, Radiometry, Calibration, Space operations, Standards development, Satellite communications, Aerospace engineering, Communication and information technologies

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Proceedings Article | 19 October 2016 Presentation + Paper

Current status of the dual-frequency precipitation radar on the global precipitation measurement core spacecraft and the new version of GPM standard products

K. Furukawa, T. Nio, T. Konishi, T. Masaki, T. Kubota, R. Oki, T. Iguchi

Proceedings Volume 10000, 1000003 (2016) https://doi.org/10.1117/12.2240907

KEYWORDS: Radar, Satellites, Microwave radiation, Calibration, Space operations, Aerospace engineering, Communication and information technologies, Satellite imaging, Ku band, Ka band

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Proceedings Article | 12 October 2015 Paper

Current status of the dual-frequency precipitation radar on the global precipitation measurement core spacecraft

K. Furukawa, T. Nio, T. Konishi, R. Oki, T. Masaki, T. Kubota, T. Iguchi, H. Hanado

Proceedings Volume 9639, 96390G (2015) https://doi.org/10.1117/12.2193868

KEYWORDS: Radar, Calibration, Space operations, Satellites, Microwave radiation, Observatories, Radiometry, Antennas, Aerospace engineering, Communication and information technologies

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The Dual-frequency Precipitation Radar (DPR) on the Global Precipitation Measurement (GPM) core satellite was developed by Japan Aerospace Exploration Agency (JAXA) and National Institute of Information and Communications Technology (NICT). The GPM is a follow-on mission of the Tropical Rainfall Measuring Mission (TRMM). The objectives of the GPM mission are to observe global precipitation more frequently and accurately than TRMM. The frequent precipitation measurement about every three hours will be achieved by some constellation satellites with microwave radiometers (MWRs) or microwave sounders (MWSs), which will be developed by various countries. The accurate measurement of precipitation in mid-high latitudes will be achieved by the DPR. The GPM core satellite is a joint product of National Aeronautics and Space Administration (NASA), JAXA and NICT. NASA developed the satellite bus and the GPM Microwave Imager (GMI), and JAXA and NICT developed the DPR. JAXA and NICT developed the DPR through procurement. The configuration of precipitation measurement using active radar and a passive radiometer is similar to TRMM. The major difference is that DPR is used in GPM instead of the precipitation radar (PR) in TRMM. The inclination of the core satellite is 65 degrees, and the nominal flight altitude is 407 km. The non-sun-synchronous circular orbit is necessary for measuring the diurnal change of rainfall similarly to TRMM. The DPR consists of two radars, which are Ku-band (13.6 GHz) precipitation radar (KuPR) and Ka-band (35.5 GHz) precipitation radar (KaPR). Both KuPR and KaPR have almost the same design as TRMM PR. The DPR system design and performance were verified through the ground test. GPM core observatory was launched at 18:37:00 (UT) on February 27, 2014 successfully. DPR orbital check out was completed in May 2014. The results of orbital checkout show that DPR meets its specification on orbit. After completion of initial checkout, DPR started Normal Operations and Initial Calibration and Validation period was started. JAXA conducted internal calibrations, external calibrations and phase code changes to mitigate KuPR sidelobe clutter effect. JAXA evaluated these operations results and concluded that DPR data could go public. DPR products were released to the public on Sep. 2, 2014 and Normal Observation Operation period was started. JAXA is continuing DPR trend monitoring, calibration operations to confirm that DPR keeps its function and performance on orbit.

Proceedings Article | 9 November 2012 Paper

GPM science status in Japan

Kenji Nakamura, Riko Oki, Toshio Iguchi

Proceedings Volume 8528, 85281B (2012) https://doi.org/10.1117/12.977256

KEYWORDS: Meteorology, Radar, Algorithm development, Radiometry, Microwave radiation, Satellites, Signal attenuation, Particles, Ka band, Reflectivity

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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 | 8 November 2012 Paper

Development of precipitation retrieval algorithm for passive microwave sounder over land

S. Kida, T. Kubota, M. Kachi, S. Shige, R. Oki

Proceedings Volume 8523, 852309 (2012) https://doi.org/10.1117/12.977278

KEYWORDS: Algorithm development, Meteorology, Microwave radiation, Scattering, Satellites, Terbium, Clouds, Particles, Aerospace engineering, Atmospheric particles

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Proceedings Article | 16 November 2010 Paper

Dual-frequency radar (DPR) and the global precipitation measurement (GPM) in Japan

Kenji Nakamura, Riko Oki, Toshio Iguchi

Proceedings Volume 7856, 78560M (2010) https://doi.org/10.1117/12.871120

KEYWORDS: Radar, Signal attenuation, Satellites, Meteorology, Ka band, Radiometry, Microwave radiation, Antennas, Algorithm development, Reflectivity

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Proceedings Article | 13 October 2010 Paper

Status of development of the GPM Dual-frequency Precipitation Radar (DPR), algorithm development, and ground validation activities

Misako Kachi, Takeshi Miura, Riko Oki, Shuji Shimizu, Takuji Kubota, Naofumi Yoshida, Yasutoshi Hyakusoku, Kinji Furukawa, Masahiro Kojima, Toshio Iguchi, Kenji Nakamura

Proceedings Volume 7826, 78260A (2010) https://doi.org/10.1117/12.865552

KEYWORDS: Algorithm development, Radar, Satellites, Microwave radiation, Meteorology, Calibration, Ka band, Detection and tracking algorithms, Signal attenuation, Standards development

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Proceedings Article | 23 September 2009 Paper

Status of algorithm development and CAL/VAL plans in the JAXA GPM project

Misako Kachi, Riko Oki, Shuji Shimizu, Takuji Kubota, Naofumi Yoshida, Toshio Iguchi, Kenji Nakamura

Proceedings Volume 7474, 74740P (2009) https://doi.org/10.1117/12.830261

KEYWORDS: Satellites, Algorithm development, Microwave radiation, Radar, Meteorology, Radiometry, Imaging systems, Satellite imaging, Calibration, Signal attenuation

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Proceedings Article | 9 October 2008 Paper

Development of the DPR algorithms and products for GPM

Misako Kachi, Shuji Shimizu, Naofumi Yoshida, Takuji Kubota, Riko Oki, Toshio Iguchi

Proceedings Volume 7106, 71060S (2008) https://doi.org/10.1117/12.801875

KEYWORDS: Satellites, Algorithm development, Radar, Microwave radiation, Meteorology, Radiometry, Sensors, Earth observing sensors, Floods, Clouds

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Proceedings Article | 17 October 2007 Paper

Development of the DPR algorithms and products for GPM

Shuji Shimizu, Riko Oki, Misako Kachi, Hiroshi Hanado, Masahiro Kojima, Toshio Iguchi, Kenji Nakamura

Proceedings Volume 6744, 67440I (2007) https://doi.org/10.1117/12.739032

KEYWORDS: Satellites, Radar, Floods, Microwave radiation, Sensors, Algorithm development, Meteorology, Radiometry, Earth observing sensors, Climatology

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Proceedings Article | 17 October 2007 Paper

CEOS precipitation constellation

Steven Neeck, Riko Oki

Proceedings Volume 6744, 674428 (2007) https://doi.org/10.1117/12.746142

KEYWORDS: Satellites, Sensors, Climatology, Standards development, Satellite communications, Microwave radiation, Prototyping, Data archive systems, Algorithm development, Environmental sensing

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Proceedings Article | 30 November 2006 Paper

Global precipitation measurement (GPM) mission and its application for flood monitoring

Misako Kachi, Riko Oki, Shuji Shimizu, Masahiro Kojima

Proceedings Volume 6407, 64070A (2006) https://doi.org/10.1117/12.694043

KEYWORDS: Satellites, Floods, Microwave radiation, Radar, Radiometry, Climatology, Earth observing sensors, Sensors, Clouds, Eye

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Proceedings Article | 3 October 2006 Paper

Development of spaceborne dual frequency precipitation radar for the global precipitation measurement mission

Shuji Shimizu, Riko Oki, Masahiro Kojima, Toshio Iguchi, Kenji Nakamura

Proceedings Volume 6361, 63610O (2006) https://doi.org/10.1117/12.694963

KEYWORDS: Satellites, Radar, Meteorology, Antennas, Radiometry, Microwave radiation, Algorithm development, Control systems, Climatology, Waveguides

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Proceedings Article | 21 October 2005 Paper

Global precipitation measurement (GPM) mission and dual-frequency precipitation radar (DPR)

Kenji Nakamura, Riko Oki, Toshio Iguchi, Masahiro Kojima

Proceedings Volume 5978, 597806 (2005) https://doi.org/10.1117/12.629624

KEYWORDS: Satellites, Radar, Radiometry, Meteorology, Microwave radiation, Algorithm development, Climatology, Antennas, Solids, Systems modeling

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Proceedings Article | 18 April 2003 Paper

EarthCARE-Earth clouds, aerosol and radiation explorer: it's objectives and Japanese sensor designs

Toshiyoshi Kimura, Kayoko Kondo, Hiroshi Kumagai, Hiroshi Kuroiwa, Chu Ishida, Riko Oki, Akihiko Kuze, Makoto Suzuki, Hajime Okamoto, Rouichi Imasu, Teruyuki Nakajima

Proceedings Volume 4882, (2003) https://doi.org/10.1117/12.462582

KEYWORDS: Clouds, Aerosols, Fourier transforms, Sensors, Radar, LIDAR, Doppler effect, Earth's atmosphere, Satellites, Atmospheric particles

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Proceedings Article | 8 April 2003 Paper

System definition of the ESA Earth Explorer EarthCARE mission

Jean-Loup Bezy, Wolfgang Leibrandt, Pierluigi Silvestrin, Pedro Baptista, Akihito Kawamura, Riko Oki, Makoto Suzuki, Hiroshi Kumagai

Proceedings Volume 4881, (2003) https://doi.org/10.1117/12.463030

KEYWORDS: Clouds, Fourier transforms, Satellites, Sensors, Radar, Aerosols, LIDAR, Multispectral imaging, Earth's atmosphere, Atmospheric particles

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Proceedings Article | 8 February 2002 Paper

Mission and instrument concept of EarthCARE FTS

Makoto Suzuki, Kayoko Kondo, Shunsuke Ichizawa, Sho Tsujimaru, Takuki Sano, Riko Oki, Teruyuki Nakajima, Haruhisa Shimoda, Toshihiro Ogawa

Proceedings Volume 4486, (2002) https://doi.org/10.1117/12.455113

KEYWORDS: Fourier transforms, Clouds, Aerosols, Atmospheric modeling, Sensors, Satellites, Climatology, Earth's atmosphere, Calibration, Spectral resolution

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Proceedings Article | 21 December 2000 Paper

Comparison of TRMM/PR rain rate with ground-based observation

Riko Oki, Toshiaki Kozu

Proceedings Volume 4152, (2000) https://doi.org/10.1117/12.410594

KEYWORDS: Meteorology, Error analysis, Radar, Satellites, Reflectivity, Statistical analysis, Calibration, Environmental sensing, Data analysis, Data acquisition

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Proceedings Article | 21 December 2000 Paper

Preliminary study of the use of TRMM TMI data in the Japan Meteorological Agency numerical weather prediction model

Misako Kachi, Yoshihiko Tahara, Riko Oki

Proceedings Volume 4152, (2000) https://doi.org/10.1117/12.410601

KEYWORDS: Data modeling, Satellites, Atmospheric modeling, Microwave radiation, Clouds, Meteorology, Calibration, Radiation effects, Temperature metrology, Meteorological satellites

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