Inverse procedure for high‐latitude ionospheric electrodynamics: Analysis of satellite‐borne magnetometer data
Inverse procedure for high‐latitude ionospheric electrodynamics: Analysis of satellite‐borne magnetometer data
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高纬度电离层电动力学的逆过程：星载磁力计数据分析
DOI：
10.1002/2014ja020565
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
B. Anderson
中科院分区：
文献类型：
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作者：
T. Matsuo;D. Knipp;A. Richmond;L. Kilcommons;B. Anderson
本文分析了国防气象卫星计划（DMSP）F - 15、F - 16、F - 17和F - 18卫星以及铱星星座上磁强计的数据，在2010年5月29 - 30日期间，使用一种针对高纬度电离层电动力学的反演方法。铱星磁强计数据通过主动磁层与行星电动力学响应实验（AMPERE）项目获取。这里介绍的方法建立在电离层电动力学同化映射方法的基础上，但对先验模型的不确定性进行了更全面的处理，以便从不规则分布的观测数据中对电动力学变量的完整极区图进行最优推断。该方法能够对分析相关的不确定性提供一种客观的度量。交叉验证分析中，将DMSP数据用作独立的验证数据集，结果表明，仅从AMPERE数据得出的DMSP扰动磁场的空间预测，中值差异为30 - 50纳特。在约20%的总样本中可看到大于100纳特的差异，其位置和大小通常与先前确定的DMSP和AMPERE数据集之间的差异一致。与AMPERE提供的场向电流（FAC）产品相比，由此得出的场向电流模式呈现出更明显的空间模式，且没有虚假的高频振荡特征。在一次磁云事件期间，在四种不同的行星际磁场（IMF）条件下，根据AMPERE和DMSP数据估算的环向磁势和场向电流图，展示了行星际磁场对高纬度电动力学的控制以及未来科学研究的机会。
This paper presents an analysis of data from the magnetometers on board the Defense Meteorological Satellite Program (DMSP) F‐15, F‐16, F‐17, and F‐18 satellites and the Iridium satellite constellation, using an inverse procedure for high‐latitude ionospheric electrodynamics, during the period of 29–30 May 2010. The Iridium magnetometer data are made available through the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) program. The method presented here is built upon the assimilative mapping of ionospheric electrodynamics procedure but with a more complete treatment of the prior model uncertainty to facilitate an optimal inference of complete polar maps of electrodynamic variables from irregularly distributed observational data. The procedure can provide an objective measure of uncertainty associated with the analysis. The cross‐validation analysis, in which the DMSP data are used as independent validation data sets, suggests that the procedure yields the spatial prediction of DMSP perturbation magnetic fields from AMPERE data alone with a median discrepancy of 30–50 nT. Discrepancies larger than 100 nT are seen in about 20% of total samples, whose location and magnitude are generally consistent with the previously identified discrepancy between DMSP and AMPERE data sets. Resulting field‐aligned current (FAC) patterns exhibit more distinct spatial patterns without spurious high‐frequency oscillatory features in comparison to the FAC products provided by AMPERE. Maps of the toroidal magnetic potential and FAC estimated from both AMPERE and DMSP data under four distinctive interplanetary magnetic field (IMF) conditions during a magnetic cloud event demonstrate the IMF control of high‐latitude electrodynamics and the opportunity for future scientific investigation.