How sensitive is the recovery of stratospheric ozone to changes in concentrations of very short-lived bromocarbons?
How sensitive is the recovery of stratospheric ozone to changes in concentrations of very short-lived bromocarbons?
复制标题
平流层臭氧的恢复对寿命极短的溴化碳浓度变化有多敏感？
DOI：
--
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
J. Pyle
中科院分区：
文献类型：
--
作者：
Xin Yang;N. Abraham;A. Archibald;P. Braesicke;J. Keeble;P. Telford;N. Warwick;J. Pyle
抽象的。自然产生的寿命极短的物质（VSLS）几乎占目前平流层无机溴Bry的四分之一。在VSLS氧化之后，溴自由基（Br和BrO）可以催化破坏臭氧。地面排放量的可能增加或这些可变空间位置的溴碳向平流层的迁移在多大程度上能够抵消《蒙特利尔议定书》规定的卤素削减的影响，这是一个重要的政策问题。在这里，通过使用一个化学气候模型，UM-UKCA，我们调查的影响，一个假设的加倍（增加5 ppt Bry）的VSLS溴碳对臭氧和臭氧的变化如何取决于氯和溴的背景浓度。我们的模式试验表明，对于VSLS产生的Bry增加5 ppt，南半球平流层最低层臭氧的年平均减少可达10%，而北方半球臭氧的年平均减少较小（4-6%）。对臭氧柱影响最大的是南极春季。在平流层氯含量高的背景下，垂直表面光散射的负荷比在平流层氯含量低的背景下增加了一倍，臭氧的减少量明显更大，这表明了卤素间反应的重要性。例如，当平流层Cly约为3 ppb（目前）时，高纬度低平流层臭氧浓度作为Bry的函数的下降幅度比Cly约为0.8 ppb（工业化前或预测的未来情况）高出约30-40%。溴将在未来的臭氧层中发挥重要作用。然而，即使来自天然VSLS的溴水平在本世纪后期显著增加，臭氧浓度的变化也可能主要是人为氯的减少。我们的计算表明，对于5个百分点的增加Bry从VSLS，南极臭氧洞的恢复日期可能会推迟约6-8年，这取决于Cly水平。
Abstract. Naturally produced very short-lived substances (VSLS) account for almost a quarter of the current stratospheric inorganic bromine, Bry. Following VSLS oxidation, bromine radicals (Br and BrO) can catalytically destroy ozone. The extent to which possible increases in surface emissions or transport of these VSLS bromocarbons to the stratosphere could counteract the effect of halogen reductions under the Montreal Protocol is an important policy question. Here, by using a chemistry–climate model, UM-UKCA, we investigate the impact of a hypothetical doubling (an increase of 5 ppt Bry) of VSLS bromocarbons on ozone and how the resulting ozone changes depend on the background concentrations of chlorine and bromine. Our model experiments indicate that for the 5 ppt increase in Bry from VSLS, the ozone decrease in the lowermost stratosphere of the Southern Hemisphere (SH) may reach up to 10% in the annual mean; the ozone decrease in the Northern Hemisphere (NH) is smaller (4–6%). The largest impact on the ozone column is found in the Antarctic spring. There is a significantly larger ozone decrease following the doubling of the VSLS burden under a high stratospheric chlorine background than under a low chlorine background, indicating the importance of the inter-halogen reactions. For example, the decline in the high-latitude, lower-stratospheric ozone concentration as a function of Bry is higher by about 30–40% when stratospheric Cly is ~ 3 ppb (present day), compared with Cly of ~ 0.8 ppb (a pre-industrial or projected future situation). Bromine will play an important role in the future ozone layer. However, even if bromine levels from natural VSLS were to increase significantly later this century, changes in the concentration of ozone will likely be dominated by the decrease in anthropogenic chlorine. Our calculation suggests that for a 5 ppt increase in Bry from VSLS, the Antarctic ozone hole recovery date could be delayed by approximately 6–8 years, depending on Cly levels.
登录
查看更多内容
OP3期间海洋大陆热带边界层的三溴甲烷
影响因子：
6.3
作者：
Pyle J
通讯作者：
Pyle J
影响因子：
6.3
作者：
Braesicke P
通讯作者：
Braesicke P
三溴甲烷、二溴甲烷和碘甲烷的全球海空通量气候学
影响因子：
6.3
作者：
Ziska F
通讯作者：
Ziska F
臭氧变化引起南半球持续的环流差异：化学气候模型和观测研究
DOI：
10.5194/acpd-13-8455-2013
发表时间：
2013
期刊：
--
影响因子：
--
作者：
Braesicke P
通讯作者：
Braesicke P