Effects of High‐Latitude Forcing Uncertainty on the Low‐Latitude and Midlatitude Ionosphere
Effects of High‐Latitude Forcing Uncertainty on the Low‐Latitude and Midlatitude Ionosphere
复制标题
高纬度强迫不确定性对低纬度和中纬度电离层的影响
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
A. Richmond
中科院分区：
文献类型：
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作者：
N. Pedatella;G. Lu;A. Richmond
使用热层-电离层-电动力学环流模式（TIE - GCM）进行了整体模拟，以了解高纬度强迫不确定性对低纬度和中纬度电离层响应2010年4月地磁风暴的作用。该系综是通过扰动电离层电动力学（AMIE）同化映射中的高纬度电势或极光能量通量而产生的。高纬度电势扰动的模拟结果表明，低纬度和中纬度电离层对地磁风暴的响应具有显著的集合内变率，NmF2变化的集合标准差达到平均变化的50-100%。当扰动极光能量通量时，不会看到如此大的系综内变率。在这种情况下，强迫不确定性的影响主要局限于高纬度地区。因此，我们得出结论，在模拟低纬度和中纬度电离层对地磁风暴的响应时，高纬度电场的规范是一个重要的不确定性来源。对结果的多元线性回归分析表明，赤道电场、中性风和中性成分的风暴时间变化的不确定性都可能导致电离层电子密度的不确定性。由于对高纬度强迫的不完全了解，本研究的结果提供了对低纬度和中纬度电离层对地磁风暴响应模拟中可能存在的不确定性的见解。
Ensemble simulations are performed using the Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (TIE‐GCM) in order to understand the role of high‐latitude forcing uncertainty on the low‐latitude and midlatitude ionosphere response to the April 2010 geomagnetic storm. The ensemble is generated by perturbing either the high‐latitude electric potential or auroral energy flux in the assimilative mapping for ionosphere electrodynamics (AMIE). Simulations with perturbed high‐latitude electric potential result in substantial intraensemble variability in the low‐latitude and midlatitude ionosphere response to the geomagnetic storm, and the ensemble standard deviation for the change in NmF2 reaches 50–100% of the mean change. Such large intraensemble variability is not seen when perturbing the auroral energy flux. In this case, the effects of the forcing uncertainty are primarily confined to high latitudes. We therefore conclude that the specification of high‐latitude electric fields is an important source of uncertainty when modeling the low‐latitude and midlatitude ionosphere response to a geomagnetic storm. A multiple linear regression analysis of the results indicates that uncertainty in the storm time changes in the equatorial electric fields, neutral winds, and neutral composition can all contribute to the uncertainty in the ionosphere electron density. The results of the present study provide insight into the possible uncertainty in simulations of the low‐latitude and midlatitude ionosphere response to geomagnetic storms due to imperfect knowledge of the high‐latitude forcing.