Kyushu University [Nawo Eguchi (Associate Professor) Research Institute for Applied Mechanics, Center for Oceanic and Atmospheric Research]

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Nawo Eguchi
Associate Professor
Center for Oceanic and Atmospheric Research
Research Institute for Applied Mechanics
Last modified date：2023.10.05

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Department of Interdisciplinary Engineering Sciences
Interdisciplinary Graduate School of Engineering Sciences

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Total Priod of education and research career in the foreign country

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1.	Nawo Eguchi and Yukio Yoshida, A high-level cloud detection method utilizing the GOSAT TANSO-FTS water vapor saturated band, Atmospheric Measurement Technique, 10.5194/amt-12-389-2019, 12, 1, 389-403, 2019.01.
2.	Nawo Eguchi, Kunihiko Kodera, and Tomoe Nasuno, A global non-hydrostatic model study of a downward coupling through the tropical tropopause layer during a stratospheric sudden warming, Atmospheric Chemistry and Physics, 10.5194/acp-15-297-2015, 15, 1, 297-304, 2015.01.
3.	Yukio Yoshida, Yoshifumi Ota, Nawo Eguchi, Nobuyuki Kikuchi, Koji Nobuta, Ha Tran, Isamu Morino, and Tatsuya Yokota, Retrieval algorithm for CO2 and CH4 column abundances from short-wavelength infrared spectral observations by the Greenhouse gases observing satellite, Atmospheric Measurement Technique, 10.5194/amt-4-717-2011, 4, 4, 717-734, 2011.04.
4.	Nawo Eguchi, Ryu Saito, Tazu Saeki, Yumiko Nakatsuka, Dmitry Belikov, and Shamil Maksyutov, A priori covariance estimation for CO2 and CH4 retrievals, Journal of Geophysical Research-Atmosphere, 10.1029/2009JD013269, 115, D10, D10215 1-16, 2010.05, We derive the a priori covariance matrices of CO2 and CH4 for the retrieval of their profiles and columns from satellite spectral data. The monthly a priori covariance matrices of CO2 and CH4 at each grid cell (0.5° × 0.5°) on the globe are calculated using simulated data from the atmospheric tracer transport model. The a priori covariance matrix is defined as the sum of the bias and noise components, where the bias is obtained from the difference in seasonal cycle between simulated data and observation-based reference data, and the noise is defined as synoptic and interannual variations. The use of simulated data as well as observation-based reference data enables realistic variance and covariance values to be obtained for each temporal component. The seasonal bias is approximately 2 ppm for CO2 and 20 ppb for CH4. A large difference in synoptic variations is obtained between simulated and reference data over the source region, especially over land. The interannual variances derived from the reference data show maximum values (4 ppm2 for CO2 and 220 ppb2 for CH4) in northern midlatitudes. Global data sets of a priori covariance matrices for CO2 and CH4 are now available for the retrieval of concentrations using satellite spectral data. Furthermore, the data set has the potential to be applied in studies in other fields, including estimates of CO2 flux error using inverse modeling and planning for ground-based observation networks..
5.	Tatsuya Yokota, Yukio Yoshida, Nawo Eguchi, Yoshifumi Ota, Tomoaki Tanaka, Hiroshi Watanabe and Shamil Maksyutov, Global Concentrations of CO2 and CH4 Retrieved From GOSAT: First Preliminary Results, Scientific Online Letters on the Atmosphere, 10.2151/sola.2009‒041, 5, 1, 160-163, 2009.10, The Greenhouse Gases Observing Satellite (GOSAT) was launched on January 23, 2009, to monitor global atmospheric levels of CO2 and CH4 from space. GOSAT started initial operation of its instruments after an initial satellite system check. Although the radiant data obtained by the GOSAT instruments are currently in the preliminary stages of calibration and validation, the spectral absorption features of CO2 and CH4 are clearly identifiable. An initial retrieval of these gaseous concentrations was performed for measurement scenes of cloud-free conditions over land. These results showed that column-averaged dry air mole fractions of both CO2 and CH4 in the northern hemisphere were higher than those in the southern hemisphere. These latitudinal differences agree with data obtained from groundbased sources and other satellite observations; however, the absolute values of the gaseous concentrations from GOSAT data seem to have been underestimated. Calibrations as well as validation should be conducted to improve the quality of GOSAT retrievals..

1.	Kunihiko Kodera, Nawo Eguchi, Beatriz M. Funatsu, Rei Ueyama, Chantal Claud, Influence of tropical lower stratospheric cooling on extreme deep convective activity and tropical cyclones, Asia Oceania Geosciences Society (AOGS)16th Annual Meeting, 2019.07.
2.	Nawo Eguchi, Kunihiko Kodera, Rei Ueyama, Hisahiro Takashima, and Makoto Deushi, Rapid transport of carbon monoxide and water vapor from troposphere to stratosphere via tropical convection during stratospheric sudden warming, American Geophysical Union (AGU) Fall Meeting 2015, 2015.12.
3.	Nawo Eguchi, Kunihiko Kodera, Rei Ueyama, and Hisahiro Takashima, Rapid increase of carbon monoxide concentration in the tropical lower stratosphere during stratospheric sudden warming in January 2010, The 95th AMS Annual Meeting, 2015.01.
4.	Nawo Eguchi, Kunihiko Kodera, and Tomoe Nasuno, Downward coupling process through TTL during a stratospheric sudden warming: a case study using a global non-hydrostatic model, SPARC General Assembly 2014, 2014.01.
5.	Toshihiko Hirooka, Chihiro Iida, and Nawo Eguchi, Circulation changes in the mesosphere during sudden warming events, The 12th Scientific Assembly of IAGA, 2013.08.
6.	Nawo Eguchi, Kunihiko Kodera, and Tomoe Nasuno, Impact of abrupt stratospheric dynamical change on Tropical Tropopause Layer, US/Japan TTL joint workshop, 2012.10.
7.	Nawo Eguchi, Kunihiko Kodera and Tomoe Nasuno, Stratospheric sudden warming impact on the tropical troposphere seen in NICAM simulation, Workshop on Stratospheric Sudden Warming and its Role in Weather and Climate Variation, 2012.02.
8.	Nawo Eguchi, Tadahiro Hayasaka, and Masahiro Sawada, Characteristics of “YAMASE” Cloud : A case study of summer 2003, Fifth Korea-Japan-China Joint Conference on Meteorology, 2011.10.
9.	Nawo Eguchi, Yukio Yoshida, Isamu Morino, Nobuhiro Kikuchi, Tazu Saeki, Makoto Inoue, Osamu Uchino, Shamil Maksyutov, Hiroshi Watanabe, and Tatsuya Yokota, Seasonal variations of greenhouse gas column-averaged dry air mole fractions retrieved from SWIR spectra of GOSAT TANSO-FTS, The IEEE International Geoscience and Remote Sensing Symposium (IGARSS), 2011.07.