Ozone depletion events in the Arctic spring of 2019: a new modeling approach to bromine emissions
Ozone depletion events in the Arctic spring of 2019: a new modeling approach to bromine emissions
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DOI：
10.5194/acp-22-13495-2022
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发表时间：
2022-10
影响因子：
6.3
通讯作者：
M. Herrmann;M. Schöne;C. Borger;Simon Warnach;T. Wagner;U. Platt;E. Gutheil
中科院分区：
文献类型：
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作者：
M. Herrmann;M. Schöne;C. Borger;Simon Warnach;T. Wagner;U. Platt;E. Gutheil
抽象的。北极春季边界层经常发生臭氧消耗事件（ODE）。臭氧会被溴物质耗尽，这些溴物质很可能是在自催化反应循环中从雪、海冰或气溶胶中释放出来的。先前的常微分方程三维建模研究假设地面有无限的溴源。在本研究中，提出了一种替代排放方案，其中随着时间的推移跟踪雪中有限数量的溴化物。为此，使用天气研究和预报模型与化学 (WRF-Chem) 相结合的修改版本来研究 2019 年 2 月至 5 月北极的常微分方程。将模型数据与现场测量、臭氧探空仪飞行和卫星数据进行比较。使用第一年（FY）冰的无限溴化物假设对2009年北极春季的ODE进行的模拟转移到2019年春季，与观测结果吻合良好；然而，2009 年 4 月和 2019 年 4 月，对于 ODE 的大小和数量的高估存在一些分歧。使用有限溴化物假设的新模拟大大提高了与 2019 年 4 月在阿拉斯加乌特恰维克、斯瓦尔巴群岛齐柏林山和芬兰帕拉斯现场观测的一致性，表明海冰上的溴化物已消耗到一定程度，从而减少了溴的释放。新的模拟还略微改善了与二月和三月在这些地点的观测结果的一致性。与加拿大尤里卡和格陵兰岛北站附近的测量结果进行比较表明，多年冰和可能被雪覆盖的土地可能是重要的溴来源。然而，假设尤里卡附近可释放的溴化物含量较高，并不能消除与观察结果的所有分歧。数值结果还与通过对流层监测仪器 (TROPOMI) 观测的新反演方法生成的对流层 BrO 垂直柱密度进行了比较。 BrO 垂直柱密度 (VCD) 高于 5×1013 摩尔。 cm−2 卫星观测结果与模型结果吻合较好。然而，该模型还预测 BrO VCD 约为 3×1013 摩尔克。 cm−2 遍布整个北极以及大约 1014 摩尔克的 BrO VCD 斑块。 cm−2 未被卫星观测到，特别是在哈德逊湾附近。这表明，与北部的雪相比，哈德逊湾的雪在春末可能是较弱的溴源。
Abstract. Ozone depletion events (ODEs) are a common occurrence in the boundary layer during Arctic spring. Ozone is depleted by bromine species, which are most likely emitted from snow, sea ice, or aerosols in an autocatalytic reaction cycle. Previous three-dimensional modeling studies of ODEs assumed an infinite bromine source at the ground. In the present study, an alternative emission scheme is presented in which a finite amount of bromide in the snow is tracked over time. For this purpose, a modified version of the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) is used to study ODEs in the Arctic from February to May 2019. The model data are compared to in situ measurements, ozone sonde flights, and satellite data. A simulation of the ODEs in the Arctic spring of 2009 using the infinite-bromide assumption on first-year (FY) ice is transferred to the spring of 2019, which achieves good agreement with the observations; however, there is some disagreement in April 2009 and 2019 with respect to an overestimation concerning both the magnitude and the number of ODEs. New simulations using the finite-bromide assumption greatly improve agreement with in situ observations at Utqiaġvik, Alaska, Zeppelin Mountain, Svalbard, and Pallas, Finland, in April 2019, suggesting that bromide on the sea ice is depleted to an extent that reduces the bromine release. The new simulations also slightly improve the agreement with observations at these sites in February and March. A comparison to measurements near Eureka, Canada, and Station Nord, Greenland, shows that multi-year ice and possibly snow-covered land may be significant bromine sources. However, assuming higher releasable bromide near Eureka does not remove all disagreement with the observations. The numerical results are also compared to tropospheric-BrO vertical column densities generated with a new retrieval method from TROPOspheric Monitoring Instrument (TROPOMI) observations. BrO vertical column densities (VCDs) above 5×1013 molec. cm−2 observed by the satellite agree well with the model results. However, the model also predicts BrO VCDs of around 3×1013 molec. cm−2 throughout the Arctic and patches of BrO VCDs of around 1014 molec. cm−2 not observed by the satellite, especially near Hudson Bay. This suggests that snow at Hudson Bay may be a weaker bromine source in late spring compared to snow in the north.