Combined bromine and chlorine release from large explosive volcanic eruptions: A threat to stratospheric ozone?
Combined bromine and chlorine release from large explosive volcanic eruptions: A threat to stratospheric ozone?
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DOI：
10.1130/g34044.1
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发表时间：
2013-06-01
期刊：
影响因子：
5.8
通讯作者：
Wehrmann, H.
中科院分区：
文献类型：
--
作者：
Kutterolf, S.;Hansteen, T. H.;Wehrmann, H.
大型火山爆发将气体、气溶胶和细灰注入平流层，可能影响气候。如此大的火山喷发释放出的氯（Cl）和溴（Br）对平流层臭氧的催化破坏起着重要作用，但迄今为止，火山喷发同时向平流层灾难性释放溴和氯的全球影响尚未得到调查。用岩石学方法测定了过去70ka以来尼加拉瓜境内覆盖整个俯冲带段的14次大爆发所释放的Br。采用一种新的优化同步x射线荧光微探针装置对火山斑晶中的熔体包裹体进行了分析。单次喷发产生4- 600kt的Br输出，每次喷发平均释放27kt的Br。假设排放的卤素中有10%到达平流层，则平均Br和Cl向平流层的装载量分别为3ppt和1500ppt，两者加起来将占工业化前等效有效平流层Cl装载量的185%。因此，我们得出结论，许多大型热带火山爆发过去和现在都有可能在全球范围内大量消耗臭氧，最终形成未来的臭氧空洞。
Large explosive volcanic eruptions inject gases, aerosols, and fine ashes into the stratosphere, potentially influencing climate. Emissions of chlorine (Cl) and bromine (Br) from such large eruptions play an important role for catalytic destruction of ozone in the stratosphere, but hitherto the global effects of simultaneous catastrophic release of volcanic Br and Cl into the stratosphere have not been investigated. The Br release from 14 large explosive eruptions throughout Nicaragua covering an entire subduction zone segment in the past 70 ka was determined with petrologic methods. Melt inclusions in volcanic phenocrysts were analyzed using a new optimized synchrotron-X-ray fluorescence microprobe set-up. Single eruptions produced Br outputs of 4-600 kt, giving an average Br emission of 27 kt per eruption. Using the assumption that 10% of the emitted halogens reach the stratosphere, the average Br and Cl loading to the stratosphere would be 3 ppt and 1500 ppt, respectively, which together would account for 185% of the preindustrial equivalent effective stratospheric Cl loading. We thus conclude that many large tropical volcanic eruptions had and have the potential to substantially deplete ozone on a global scale, eventually forming future ozone holes.