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374 results on '"Uno, Itsushi"'

10. Impacts of aerosols and clouds on photolysis frequencies and photochemistry during TRACE‐P: 2. Three‐dimensional study using a regional chemical transport model

Author

Tang, Youhua, Carmichael, Gregory R, Uno, Itsushi, Woo, Jung‐Hun, Kurata, Gakuji, Lefer, Barry, Shetter, Richard E, Huang, Hao, Anderson, Bruce E, Avery, Melody A, Clarke, Antony D, and Blake, Donald R

Subjects
Climate Action, photolysis rates, chemical transport model, TRACE-P, photochemical process, aerosols and clouds, radiative influence, Meteorology & Atmospheric Sciences
Published
2003

11. Influences of biomass burning during the Transport and Chemical Evolution Over the Pacific (TRACE‐P) experiment identified by the regional chemical transport model

Author

Tang, Youhua, Carmichael, Gregory R, Woo, Jung‐Hun, Thongboonchoo, Narisara, Kurata, Gakuji, Uno, Itsushi, Streets, David G, Blake, Donald R, Weber, Rodney J, Talbot, Robert W, Kondo, Yutaka, Singh, Hanwant B, and Wang, Tao

Subjects
Climate Action, biomass burning, chemical transport model, TRACE-P, photochemical process, aerosols, radiative influence, Meteorology & Atmospheric Sciences
Published
2003

12. Contribution of biomass and biofuel emissions to trace gas distributions in Asia during the TRACE‐P experiment

Author

Woo, Jung‐Hun, Streets, David G, Carmichael, Gregory R, Tang, Youhua, Yoo, Bongin, Lee, Won‐Chan, Thongboonchoo, Narisara, Pinnock, Simon, Kurata, Gakuji, Uno, Itsushi, Fu, Qingyan, Vay, Stephanie, Sachse, Glen W, Blake, Donald R, Fried, Alan, and Thornton, Donald C

Subjects
Climate Action, bioemissions, chemical mass balance, Asian outflow, Meteorology & Atmospheric Sciences
Published
2003

13. Transport of Asian air pollution to North America

Author

Jaffe, Dan, Anderson, Theodore, Covert, Dave, Kotchenruther, Robert, Trost, Barbara, Danielson, Jen, Simpson, William, Berntsen, Terje, Karlsdottir, Sigrun, Blake, Donald, Harris, Joyce, Carmichael, Greg, and Uno, Itsushi

Subjects
Meteorology & Atmospheric Sciences
Abstract

Using observations from the Cheeka Peak Observatory in northwestern Washington State during March-April, 1997, we show that Asian anthropogenic emissions significantly impact the concentrations of a large number of atmospheric species in the air arriving to North America during spring. Isentropic back-trajectories can be used to identify possible times when this impact will be felt, however trajectories alone are not sufficient to indicate the presence of Asian pollutants. Detailed chemical and meteorological data from one of these periods (March 29th, 1997) indicates that the surface emissions were lifted into the free troposphere over Asia and then transported to North America in ~6 days.

Published
1999

23. Implementation of an ensemble Kalman filter in the Community Multiscale Air Quality model (CMAQ model v5.1) for data assimilation of ground-level PM2.5

Author

Park, Soon-Young, Dash, Uzzal Kumar, Yu, Jinhyeok, Yumimoto, Keiya, Uno, Itsushi, and Song, Chul Han

Abstract

In this study, we developed a data assimilation (DA) system for chemical transport model (CTM) simulations using an ensemble Kalman filter (EnKF) technique. This DA technique is easy to implement in an existing system without seriously modifying the original CTM and can provide flow-dependent corrections based on error covariance by short-term ensemble propagations. First, the PM2.5 observations at ground stations were assimilated in this DA system every 6 h over South Korea for the period of the KORUS–AQ campaign from 1 May to 12 June 2016. The DA performances with the EnKF were then compared to a control run (CTR) without DA and a run with three-dimensional variational (3D-Var) DA. Consistent improvements owing to the initial conditions (ICs) assimilated with the EnKF were found in the DA experiments at a 6 h interval compared to the CTR run and to the run with 3D-Var. In addition, we attempted to assimilate the ground observations from China to examine the impacts of improved boundary conditions (BCs) on the PM2.5 predictability over South Korea. The contributions of the ICs and BCs to improvements in the PM2.5 predictability were also quantified. For example, the relative reductions in terms of the normalized mean bias (NMB) were found to be approximately 27.2 % for the 6 h reanalysis run. A series of 24 h PM2.5 predictions were additionally conducted each day at 00:00 UTC with the optimized ICs. The relative reduction of the NMB was 17.3 % for the 24 h prediction run when the updated ICs were applied at 00:00 UTC. This means that after the application of the updated BCs, an additional 9.0 % reduction in the NMB was achieved for 24 h PM2.5 predictions in South Korea.

Published
2022

24. Dust Vortex in the Taklimakan Desert by Himawari-8 High Frequency and Resolution Observation

Author

Yumimoto, Keiya, Kajino, Mizuo, Tanaka, Taichu Y., Uno, Itsushi, Yumimoto, Keiya, Kajino, Mizuo, Tanaka, Taichu Y., and Uno, Itsushi

Abstract

type:Article, The Taklimakan Desert is known to be one of the world’s major sources of aeolian dust particles. Continuous images with 10-min temporal and 2-km spatial resolutions from a new-generation geostationary meteorological satellite captured the lifecycle (generation, evolution and outflow) of a previously unrecognized type of Taklimakan dust storm. The dust storm showed an anti-clockwise spiral structure and a clear core and behaved like a “dust vortex”. From image analysis, the horizontal scale and temporal lifetime of the dust vortex were estimated to be 600 km and 36 hours, respectively. We found that a strong pressure trough (cut-off low), along with a cold air mass located on the northwestern side of the Taklimakan Desert and the high mountains surrounding the Taklimakan Desert, played important roles in the formation and evolution of the dust vortex.

Published
2022

27. Aerosol observation using multi-wavelength Mie-Raman lidars of the Ad-Net and aerosol component analysis

Author

Nishizawa Tomoaki, Sugimoto Nobuo, Shimizu Atsushi, Uno Itsushi, Hara Yukari, and Kudo Rei

Subjects
Physics, QC1-999
Abstract

We deployed multi-wavelength Mie-Raman lidars (MMRL) at three sites of the AD-Net and have conducted continuous measurements using them since 2013. To analyze the MMRL data and better understand the externally mixing state of main aerosol components (e.g., dust, sea-salt, and black carbon) in the atmosphere, we developed an integrated package of aerosol component retrieval algorithms, which have already been developed or are being developed, to estimate vertical profiles of the aerosol components. This package applies to the other ground-based lidar network data (e.g., EARLINET) and satellite-borne lidar data (e.g., CALIOP/CALIPSO and ATLID/EarthCARE) as well as the other lidar data of the AD-Net.

Published
2018
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31. ACE-ASIA : Regional Climatic and Atmospheric Chemical Effects of Asian Dust and Pollution

Author

Seinfeld, John H., Carmichael, Gregory R., Arimoto, Richard, Conant, William C., Brechtel, Frederick J., Bates, Timothy S., Cahill, Thomas A., Clarke, Antony D., Doherty, Sarah J., Flatau, Piotr J., Huebert, Barry J., Kim, Jiyoung, Markowicz, Krzysztof M., Quinn, Patricia K., Russell, Lynn M., Russell, Philip B., Shimizu, Atsushi, Shinozuka, Yohei, Song, Chul H., Tang, Youhua, Uno, Itsushi, Vogelmann, Andrew M., Weber, Rodney J., Woo, Jung-Hun, and Zhang, Xiao Y.

Published
2004

50. Returning long-range PM2.5 transport into the leeward of East Asia in 2021 after Chinese economic recovery from the COVID-19 pandemic.

Author

Itahashi, Syuichi, Yamamura, Yuki, Wang, Zhe, and Uno, Itsushi

Subjects
COVID-19 pandemic, ECONOMIC recovery, STAY-at-home orders, SULFATE aerosols, COVID-19, GREENHOUSE gas mitigation
Abstract

Changes in the aerosol composition of sulfate (SO42−) and nitrate (NO3−) from 2012 to 2019 have been captured as a paradigm shift in the region downwind of China. Specifically, SO42− dramatically decreased and NO3− dramatically increased over downwind locations such as western Japan due to the faster reduction of SO2 emissions than NOx emissions and the almost constant trend of NH3 emissions from China. Emissions from China sharply decreased during COVID-19 lockdowns in February–March 2020, after which China's economic situation seemed to recover going into 2021. Given this substantial change in Chinese emissions, it is necessary to clarify the impact of long-range PM2.5 transport into the leeward of East Asia. In this study, ground-based aerosol compositions observed at three sites in western Japan were analysed. The concentrations of PM2.5, SO42− and NO3− decreased in 2020 (during COVID-19) compared with 2018–2019 (before COVID-19). In 2021 (after COVID-19), PM2.5 and NO3− increased and SO42− was unchanged. This suggests the returning long-range PM2.5 transport in 2021. From numerical simulations, the status of Chinese emissions during COVID-19 did not explain this returning impact in 2021. This study shows that the status of Chinese emissions in 2021 recovered to that before COVID-19. [ABSTRACT FROM AUTHOR]

Published
2022
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