Geomagnetic Activity Effects on CO2‐Driven Trend in the Thermosphere and Ionosphere: Ideal Model Experiments With GAIA
Geomagnetic Activity Effects on CO2‐Driven Trend in the Thermosphere and Ionosphere: Ideal Model Experiments With GAIA
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DOI：
10.1029/2020ja028607
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发表时间：
2021-01
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通讯作者：
Huixin Liu;C. Tao;H. Jin
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文献类型：
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作者：
Huixin Liu;C. Tao;H. Jin
我们使用Aeronomy全大气模式的地对地大气电离层模型研究了地磁活动（GA）对电离层和热层中CO2驱动趋势的影响。该模型揭示了三个显著特征。(1)地磁活动通常会削弱固定高度上的CO2驱动趋势。在分析的IT参数中，即使有GA的影响，热层质量密度也是CO2冷却效果最稳健的指标。(2)地磁活动可以加强或削弱hmF2和NmF2中CO2驱动的趋势，这取决于当地的时间和纬度。这使得广泛使用的线性拟合方法无法从观测中消除地磁效应。(3)CO2强迫效应与地磁强迫效应之间存在着相互依赖的关系，前者在低GA浓度下增强，后者在高CO2浓度下增强。这可能意味着，在GA下降的时期，CO2驱动的趋势将加速，而随着CO2的增加，磁暴可能会在未来产生更大的空间天气影响。这些发现提供了一个初步的模型框架，以了解从下面的CO2强迫和从上面的地磁强迫之间的相互作用。
We examine impacts of geomagnetic activity (GA) on CO2‐driven trend in the ionosphere and thermosphere using the Ground‐to‐topside Atmosphere Ionosphere model for Aeronomy whole atmosphere model. The model reveals three salient features. (1) Geomagnetic activities usually weakens the CO2‐driven trend at a fixed altitude. Among the IT parameters analyzed, the thermosphere mass density is the most robust indicator for CO2 cooling effect even with GA influences. (2) Geomagnetic activities can either strengthen or weaken the CO2‐driven trend in hmF2 and NmF2, depending on local time and latitudes. This renders the widely used linear fitting methods invalid for removing geomagnetic effects from observations. (3) An interdependency exists between the efficiency of CO2 forcing and geomagnetic forcing, with the former enhances at lower GA level, while the latter enhances at higher CO2 concentration. This could imply that the CO2‐driven trend would accelerate in periods of declining GA, while magnetic storms may have larger space weather impacts in the future with increasing CO2. These findings provide a preliminary model framework to understand interactions between the CO2 forcing from below and the geomagnetic forcing from above.