Zobrazeno 1 - 10
of 308
pro vyhledávání: '"T. Umezawa"'
Publikováno v:
Atmospheric Measurement Techniques, Vol 17, Pp 5187-5200 (2024)
Atmospheric carbonyl sulfide (COS) has received increasing attention as a potential tracer for investigating the global carbon cycle. Owing to the irreversible photosynthetic absorption of COS, changes in the atmospheric COS mole fraction can be rela
Externí odkaz:
https://doaj.org/article/600fd150472246d3861c620c84d1eae2
Autor:
T. Umezawa, S. Sugawara, K. Kawamura, I. Oyabu, S. J. Andrews, T. Saito, S. Aoki, T. Nakazawa
Publikováno v:
Atmospheric Chemistry and Physics, Vol 22, Pp 6899-6917 (2022)
Systematic measurements of atmospheric methane (CH4) mole fractions at the northern high latitudes only began in the early 1980s. Although CH4 measurements from Greenland ice cores consistently covered the period before ∼ 1900, no reliable observat
Externí odkaz:
https://doaj.org/article/e69dc28cc5cb4a14b86e13c706743803
Autor:
Y. Niwa, Y. Sawa, H. Nara, T. Machida, H. Matsueda, T. Umezawa, A. Ito, S.-I. Nakaoka, H. Tanimoto, Y. Tohjima
Publikováno v:
Atmospheric Chemistry and Physics, Vol 21, Pp 9455-9473 (2021)
Inverse analysis was used to estimate fire carbon emissions in Equatorial Asia induced by the big El Niño event in 2015. This inverse analysis is unique because it extensively used high-precision atmospheric mole fraction data of carbon dioxide (CO2
Externí odkaz:
https://doaj.org/article/1f806382ce3041528a5845ba29a99d9a
Publikováno v:
Atmospheric Chemistry and Physics, Vol 18, Pp 14851-14866 (2018)
Measurement of atmospheric carbon dioxide (CO2) is indispensable for top-down estimation of surface CO2 sources/sinks by an atmospheric transport model. Despite the growing importance of Asia in the global carbon budget, the region has only been s
Externí odkaz:
https://doaj.org/article/ddfa36deca114062900619f8153beb65
Autor:
T. Umezawa, C. A. M. Brenninkmeijer, T. Röckmann, C. van der Veen, S. C. Tyler, R. Fujita, S. Morimoto, S. Aoki, T. Sowers, J. Schmitt, M. Bock, J. Beck, H. Fischer, S. E. Michel, B. H. Vaughn, J. B. Miller, J. W. C. White, G. Brailsford, H. Schaefer, P. Sperlich, W. A. Brand, M. Rothe, T. Blunier, D. Lowry, R. E. Fisher, E. G. Nisbet, A. L. Rice, P. Bergamaschi, C. Veidt, I. Levin
Publikováno v:
Atmospheric Measurement Techniques, Vol 11, Pp 1207-1231 (2018)
We report results from a worldwide interlaboratory comparison of samples among laboratories that measure (or measured) stable carbon and hydrogen isotope ratios of atmospheric CH4 (δ13C-CH4 and δD-CH4). The offsets among the laboratories are lar
Externí odkaz:
https://doaj.org/article/8d7ca1e1efab4853a04931977e796bf9
Autor:
K. C. Wells, D. B. Millet, N. Bousserez, D. K. Henze, S. Chaliyakunnel, T. J. Griffis, Y. Luan, E. J. Dlugokencky, R. G. Prinn, S. O'Doherty, R. F. Weiss, G. S. Dutton, J. W. Elkins, P. B. Krummel, R. Langenfelds, L. P. Steele, E. A. Kort, S. C. Wofsy, T. Umezawa
Publikováno v:
Geoscientific Model Development, Vol 8, Iss 10, Pp 3179-3198 (2015)
We describe a new 4D-Var inversion framework for nitrous oxide (N2O) based on the GEOS-Chem chemical transport model and its adjoint, and apply it in a series of observing system simulation experiments to assess how well N2O sources and sinks can be
Externí odkaz:
https://doaj.org/article/1854a77753d444308dfee58167c2288b
Autor:
A. Ghosh, P. K. Patra, K. Ishijima, T. Umezawa, A. Ito, D. M. Etheridge, S. Sugawara, K. Kawamura, J. B. Miller, E. J. Dlugokencky, P. B. Krummel, P. J. Fraser, L. P. Steele, R. L. Langenfelds, C. M. Trudinger, J. W. C. White, B. Vaughn, T. Saeki, S. Aoki, T. Nakazawa
Publikováno v:
Atmospheric Chemistry and Physics, Vol 15, Iss 5, Pp 2595-2612 (2015)
Atmospheric methane (CH4) increased from ~900 ppb (parts per billion, or nanomoles per mole of dry air) in 1900 to ~1800 ppb in 2010 at a rate unprecedented in any observational records. However, the contributions of the various methane sources and s
Externí odkaz:
https://doaj.org/article/162480c7e17a46f295daf7693abee4f8
Publikováno v:
Atmospheric Chemistry and Physics, Vol 12, Iss 17, Pp 8095-8113 (2012)
We present the mixing ratio, δ13C and δD of atmospheric CH4 using commercial aircraft in the upper troposphere (UT) over the Western Pacific for the period December 2005–September 2010. The observed results were compared with those obtained using
Externí odkaz:
https://doaj.org/article/844ead7ff8244b83a7761f62b32b05b1
Publikováno v:
2023 Optical Fiber Communications Conference and Exhibition (OFC).
We fabricated a high-speed resonant cavity 4x4 photodetector array, which has two functions for high optical alignment robustness and specific wavelength selection. In the 2-SDM 2-WDM FSO communication, 100-Gbps high data rate was successfully demons
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e37955294b2f433114d442df76d27d70
https://doi.org/10.23919/ofc49934.2023.10117019
https://doi.org/10.23919/ofc49934.2023.10117019
Autor:
Y Oishi, T Adachi, N Saito, Y Ikedo, K Ishida, S Kanda, T Umezawa, S Kamioka, N Teshima, J Nakamura, S Nakamura, Y Miyake, M Iwasaki, S Wada, K Shimomura
Publikováno v:
Journal of Physics: Conference Series. 2462:012026
A small-momentum-width muon beam, so-called ultra-slow muon beam, can be generated by laser ionization of muonium. To realize efficient ultra-slow muon generation, the Lyman-alpha and below 360 nm coherent light are required to resonantly excite the
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::bcdc976627345131c2cb15122cf1335d
https://doi.org/10.1088/1742-6596/2462/1/012026
https://doi.org/10.1088/1742-6596/2462/1/012026