Chemistry of the sea ice/snowpack/atmosphere system in coastal Antarctica
Chemistry of the sea ice/snowpack/atmosphere system in coastal Antarctica
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南极洲沿海海冰/积雪/大气系统的化学
DOI：
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发表时间：
2014
期刊：
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通讯作者：
Z. Buys
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作者：
Z. Buys
对流层臭氧消耗事件（ODEs）在极地地区春季发生已有20多年的历史。在这种情况下，臭氧浓度可以在几分钟内从背景量下降到仪器检测极限以下，并保持抑制数小时至数天。臭氧的化学破坏是由与海冰区有关的卤素（特别是溴基）驱动的。有很多争论的溴自由基在大气中的来源，驱动极地边界层ODE和几个观察到的物种无机溴对测试目前的理论。
2007年，位于南极洲沿海的英国南极调查站哈雷使用化学电离质谱仪（CIMS）进行了全年测量。在春季的特定时期，CIMS被配置为测量BrO、Br 2和BrCl的浓度。此外，还对地面臭氧和当地气象进行了同步测量。
这里提出的是一个分析这些数据集的化学方面，以及更广泛的气象情况在发挥作用的ODEs的开始和终止，朝着发展一个概括的图片ODEs在哈雷。为了探索卤素释放，MISTRA模型被用来考虑特定源区的排放量，确定使用HYSPLIT空气包裹回轨迹。
已经为MISTRA开发了新的雪光化学模块，其包括在冻结表面上的液体状层中发生的化学（MISTRA-SNOW;托马斯等人，2011年）。了解这些表面过程对我们了解引发溴爆炸的化学过程非常重要。MISTRA-SNOW是利用哈雷站的测量数据进行初始化的，目的是探索在极地地区产生对流层ODE所需的化学和气象条件。
Tropospheric Ozone Depletion Events (ODEs) have been known to occur during springtime in polar regions for over 20 years. During such events, ozone concentrations can fall from background amounts to below instrumental detection limits within a few minutes and remain suppressed for on the order of hours to days. The chemical destruction of ozone is driven by halogens (especially bromine radicals) that have a source associated with the sea ice zone. There is much debate over the source of bromine radicals in the atmosphere that drive polar boundary layer ODEs and few observations of speciated inorganic bromine against which to test current theory.
In 2007, year round measurements were made at the British Antarctic Survey station Halley, in coastal Antarctica, using a Chemical Ionisation Mass Spectrometer (CIMS). During specific periods in the spring the CIMS was configured to measure concentrations of BrO, Br2 and BrCl. In addition, concurrent measurements of surface ozone and local meteorology were made.
Presented here is an analysis of these datasets in terms of both chemistry, and the broader meteorological situation at play during the onset and termination of ODEs, in a move towards developing a generalised picture for ODEs at Halley. In order to explore halogen release, the MISTRA model is used to consider emissions from specific source regions, identified using HYSPLIT air parcel back trajectories.
A new snow-photochemistry module has been developed for MISTRA which includes chemistry which takes place in the liquid like layer on frozen surfaces (MISTRA-SNOW; Thomas et al., 2011). Understanding these surface processes is of great importance to our understanding of the chemistry which initiates a bromine explosion. MISTRA-SNOW is initialised using measurements made at Halley station to explore both the chemical and meteorological conditions required to produce tropospheric ODEs in polar regions.