著者

Takashi Sekiya Yugo Kanaya Kengo Sudo Fumikazu Taketani Yoko Iwamoto Maki N. Aita Akitomo Yamamoto Katsuhiro Kawamoto

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.220-227, 2020 (Released:2020-11-25)

参考文献数

52

被引用文献数

6

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We quantified the global bromine- and iodine-mediated tropospheric ozone loss using global chemical transport model simulations. We tested three datasets of very short-lived substances (VSLS) emissions, three datasets of sea surface iodide concentrations, and an explicit representation of the effects of multi-phase reactions at the air-sea boundary on dry deposition. We then determined optimal model settings based on the evaluation using the ship-borne and aircraft-campaign observations over the ocean. Our evaluation suggested that the explicit representation of multi-phase reaction effects substantially reduced model biases of ozone in the lower troposphere (up to 11%). Moreover, the impacts of using different datasets of VSLS emissions and sea-surface iodide concentrations were relatively small. The global bromine- and iodine-mediated chemical ozone losses were estimated to account for 4% and 17% of the total chemical loss, respectively, while the global iodine-mediated dry deposition loss of ozone was estimated to account for 22% of the global total dry deposition. These bromine- and iodine-mediated ozone losses decreased surface ozone concentrations over the ocean by 10% and 23%, respectively. The observational constraint on model simulations made by this study supports that bromine and iodine substantially impact global tropospheric ozone through atmospheric chemical reactions and dry deposition processes.

著者

Takashi Sekiya Yugo Kanaya Kengo Sudo Fumikazu Taketani Yoko Iwamoto Maki N. Aita Akitomo Yamamoto Katsuhiro Kawamoto

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2020-037, (Released:2020-10-15)

被引用文献数

6

---

We quantified the global bromine- and iodine-mediated tropospheric ozone loss using global chemical transport model simulations. We tested three datasets of very short-lived substances (VSLS) emissions, three datasets of sea surface iodide concentrations, and an explicit representation of the effects of multi-phase reactions at the air-sea boundary on dry deposition. We then determined optimal model settings based on the evaluation using the ship-borne and aircraft-campaign observations over the ocean. Our evaluation suggested that the explicit representation of multi-phase reaction effects substantially reduced model biases of ozone in the lower troposphere (up to 11%). Moreover, the impacts of using different datasets of VSLS emissions and sea-surface iodide concentrations were relatively small. The global bromine- and iodine-mediated chemical ozone losses were estimated to account for 4% and 17% of the total chemical loss, respectively, while the global iodine-mediated dry deposition loss of ozone was estimated to account for 22% of the global total dry deposition. These bromine- and iodine-mediated ozone losses decreased surface ozone concentrations over the ocean by 10% and 23%, respectively. The observational constraint on model simulations made by this study supports that bromine and iodine substantially impact global tropospheric ozone through atmospheric chemical reactions and dry deposition processes.

著者

Kohei Ikeda Hiroshi Tanimoto Yugo Kanaya Fumikazu Taketani Atsushi Matsuki

出版者

公益社団法人 日本気象学会

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.19, pp.239-245, 2023 (Released:2023-10-11)

参考文献数

23

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We evaluated the mass concentration levels and long-term trends of black carbon (BC) in the historical and future scenario simulations using 12 climate models from the Coupled Model Intercomparison Project Phase 6 (CMIP6) for East Asia, the region with the largest anthropogenic emissions. By comparing them with surface observations at two regionally representative sites, Fukue and Noto, for the period of 2009-2020, we found that the CMIP6 multi-model mean was approximately two times higher than the observed BC concentrations and did not reproduce the observed decreasing trend before 2014. Sensitivity simulations of emission inventories using a chemical transport model, GEOS-Chem, suggested that the overestimation and increasing trend of Chinese BC emissions in the CMIP6 historical inventory (CEDSv2017-05-18) were responsible for the higher concentrations and opposite trends in the CMIP6 BC simulations. The direct radiative effect of BC for CEDS was estimated to be 72% larger in East Asia than that for the ECLIPSEv6b inventory, which reproduced the observed BC concentrations reasonably well.