Polar Ozone Response to Energetic Particle Precipitation Over Decadal Time Scales: The Role of Medium-Energy Electrons
Polar Ozone Response to Energetic Particle Precipitation Over Decadal Time Scales: The Role of Medium-Energy Electrons
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DOI：
10.1002/2017jd027605
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发表时间：
2018-01-16
影响因子：
4.4
通讯作者：
van de Kamp, M.
中科院分区：
文献类型：
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作者：
Andersson, M. E.;Verronen, P. T.;van de Kamp, M.
极地中层大气研究的关键挑战之一是量化高能粒子降水（EPP）的总强迫，并评估太阳活动周期时间尺度上的相关响应。对于能量在30 keV到1 MeV之间的电子，即所谓的中能电子（英语：Medium energy electrons），尤其如此，在化学气候模拟中一直缺乏对中能电子电离的充分描述。在这里，我们使用的全大气社区气候模式（WACCM），包括太阳质子事件，极光电子降水，和最近开发的EPP强迫模式。我们对比我们的结果从三个集合模拟（147年），总的耦合模式相互比较项目（CMIP 5）的第五阶段，以调查的重要性，更完整的描述EPP中层大气臭氧，奇数氢，奇数氮在十年的时间尺度。我们的结果表明，平均EPP引起的极地臭氧变化的12-24%的中间层，5-7%的中，上平流层。这种变化与以前发表的观察结果一致。对模拟结果的分析表明，在总的EPP强迫中包括CO2的重要性：除了对中间层的重大影响外，CO2还将平流层臭氧响应提高了2倍。在北方半球，冬季的动力学变率比南半球大，为了得出更可靠的结论，需要进行更长时间的模拟。
One of the key challenges in polar middle atmosphere research is to quantify the total forcing by energetic particle precipitation (EPP) and assess the related response over solar cycle time scales. This is especially true for electrons having energies between about 30keV and 1MeV, so-called medium-energy electrons (MEE), where there has been a persistent lack of adequate description of MEE ionization in chemistry-climate simulations. Here we use the Whole Atmosphere Community Climate Model (WACCM) and include EPP forcing by solar proton events, auroral electron precipitation, and a recently developed model of MEE precipitation. We contrast our results from three ensemble simulations (147 years) in total with those from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) in order to investigate the importance of a more complete description of EPP to the middle atmospheric ozone, odd hydrogen, and odd nitrogen over decadal time scales. Our results indicate average EPP-induced polar ozone variability of 12-24% in the mesosphere, and 5-7% in the middle and upper stratosphere. This variability is in agreement with previously published observations. Analysis of the simulation results indicate the importance of inclusion of MEE in the total EPP forcing: In addition to the major impact on the mesosphere, MEE enhances the stratospheric ozone response by a factor of 2. In the Northern Hemisphere, where wintertime dynamical variability is larger than in the Southern Hemisphere, longer simulations are needed in order to reach more robust conclusions.