The photolysis of FeOH and its effect on the bottomside of the mesospheric Fe layer
The photolysis of FeOH and its effect on the bottomside of the mesospheric Fe layer
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DOI：
10.1002/2015gl067241
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发表时间：
2016-02
影响因子：
5.2
通讯作者：
T. Viehl;J. Plane;W. Feng;J. Höffner
中科院分区：
文献类型：
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作者：
T. Viehl;J. Plane;W. Feng;J. Höffner
在中层上层和热层下层的金属层是通过流星烧蚀产生的。它们对于了解这一大气区域的温度结构、动力学和化学性质非常重要。最近的激光雷达观测表明，与太阳辐射相关的铁层底部有规律的向下延伸。在这项研究中，我们结合联合收割机激光雷达观测，量子化学计算和模型模拟表明，这种底部的扩展主要是由光解的FeOH。我们确定光解速率为J（FeOH）=6±3×10−3 s−1。我们还表明，反应FeOH+H→FeO+H2是在中间层温度比以前的估计慢。有了这些更新的速率系数，我们能够显着提高铁层底部的建模。计算进一步表明，在阳光照射期间，FeOH几乎完全耗尽。这可能对中层大气中的云核有影响。
Metal layers in the upper mesosphere and lower thermosphere are created through meteoric ablation. They are important for understanding the temperature structure, dynamics, and chemistry of this atmospheric region. Recent lidar observations have shown a regular downward extension of the Fe layer bottomside which correlates with solar radiation. In this study we combine lidar observations, quantum chemical calculations, and model simulations to show that this bottomside extension is primarily caused by photolysis of FeOH. We determine the photolysis rate to be J(FeOH)=6±3×10−3 s−1. We also show that the reaction FeOH+H→FeO+H2 is slower at mesospheric temperatures than previous estimates. With these updated rate coefficients, we are able to significantly improve the modeling of the Fe layer bottomside. The calculations further show the nearly complete depletion of FeOH during sunlit periods. This may have implications for cloud nuclei in the middle atmosphere.