北極対流圏における反応性臭素の発生源と影響を長期観測で解明 (Sources and Impacts of Reactive Bromine in the Arctic Troposphere Revealed by Long-Term Observations)

2026-05-15 合肥物質科学研究院(HFIPS)

中国科学院合肥物质科学研究院(HFIPS)などの研究チームは、北極圏対流圏における反応性臭素(BrO)の発生源と大気酸化能への影響を長期観測と化学輸送モデル「p-TOMCAT」により解明した。研究では、中国北極黄河基地で10年以上にわたり独自開発のMAX-DOAS装置を用いてBrOとエアロゾル消散プロファイルを連続観測した。その結果、海氷上の吹雪(blowing snow)が反応性臭素放出の主要因であり、海塩エアロゾル表面での再循環反応が高濃度BrOの維持に重要であることが判明した。また、多年氷由来の吹雪が海氷起源臭素排出量の50%以上を占め、従来重視されてきた一年氷と同程度に重要であることが示された。研究成果は、北極春季のオゾン破壊現象や気候変動下での大気化学変化の理解向上に貢献する。

北極対流圏における反応性臭素の発生源と影響を長期観測で解明 (Sources and Impacts of Reactive Bromine in the Arctic Troposphere Revealed by Long-Term Observations)
Monthly median sea ice age (a–c) and the frequency of air masses along the 5 d backward trajectories when the air masses are below 500 m during BEEs (d–f) and non-BEEs (g–i) in Ny-Ålesund for March, April, and May during 2017–2023. (Image by LI Qidi)

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ニーオーレスンにおける対流圏臭素一酸化物:発生源分析と大気化学への影響 Tropospheric bromine monoxide in Ny-Ålesund: source analysis and impacts on atmospheric chemistry

Qidi Li, Yuhan Luo, Xin Yang, Bianca Zilker, Andreas Richter, Ke Dou, Haijin Zhou, Kai Zhan, Fuqi Si, and Wenqing Liu
Atmospheric Chemistry and Physics  Published:08 May 2026
DOI:https://doi.org/10.5194/acp-26-6165-2026

Abstract

Arctic tropospheric bromine monoxide (BrO) plays a critical role in atmospheric chemistry, particularly during springtime ozone depletion events. While sources such as sea ice, open ocean, aerosols, and snowpack have been proposed, their relative contributions remain uncertain. In this study, we addressed this uncertainty using long-term Multi-Axis Differential Optical Absorption Spectroscopy observations of BrO and aerosol profiles in Ny-Ålesund, Svalbard (78.92° N, 11.93° E), collected from March–May 2017–2023. BrO enhancements are positively correlated with aerosol extinction, indicating a close association with airborne particles, as supported by a Chemistry Transport Model (p-TOMCAT) simulations showing that heterogeneous recycling on aerosols is essential for sustaining elevated BrO levels. Five-day backward trajectories (0–3 km) showed significant BrO correlation with sea-ice contact time, particularly over multi-year ice (MYI) regions, which contributes comparably to first-year ice (FYI) regions in the total blowing-snow-sourced bromine flux, highlighting the comparable importance of snow over MYI and FYI regions in driving bromine explosion events. In addition, strong winds cause enhanced reactive bromine release from the sea ice. BrO and aerosol variability show a seasonal shift, with sea ice dominating in early spring and open ocean influence increasing toward late spring. BrO correlated negatively with surface ozone and mercury, indicating that enhanced bromine drives both ozone and mercury depletion. In particular, observed BrO correlated positively with modelled blowing-snow-sourced sea salt aerosol and the corresponding bromine emission fluxes from blowing snow. Snowpack-sourced bromine fluxes also correlated with BrO, although disentangling release processes remains challenging.

1702地球物理及び地球化学
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