Abstract. The high-latitude atmosphere is a dynamic region with processes that respond to forcing from the Sun, magnetosphere, neutral atmosphere, and ionosphere. Historically, the dominance of magnetosphere–ionosphere interactions has motivated upper atmospheric studies to use magnetic coordinates when examining magnetosphere–ionosphere–thermosphere coupling processes. However, there are significant differences between the dominant interactions within the polar cap, auroral oval, and equatorward of the auroral oval. Organising data relative to these boundaries has been shown to improve climatological and statistical studies, but the process of doing so is complicated by the shifting nature of the auroral oval and the difficulty in measuring its poleward and equatorward boundaries. This study presents a new set of open–closed magnetic field line boundaries (OCBs) obtained from Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) magnetic perturbation data. AMPERE observations of field-aligned currents (FACs) are used to determine the location of the boundary between the Region 1 (R1) and Region 2 (R2) FAC systems. This current boundary is thought to typically lie a few degrees equatorward of the OCB, making it a good candidate for obtaining OCB locations. The AMPERE R1–R2 boundaries are compared to the Defense Meteorological Satellite Program Special Sensor J (DMSP SSJ) electron energy flux boundaries to test this hypothesis and determine the best estimate of the systematic offset between the R1–R2 boundary and the OCB as a function of magnetic local time. These calibrated boundaries, as well as OCBs obtained from the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) observations, are validated using simultaneous observations of the convection reversal boundary measured by DMSP. The validation shows that the OCBs from IMAGE and AMPERE may be used together in statistical studies, providing the basis of a long-term data set that can be used to separate observations originating inside and outside of the polar cap.

中文翻译：

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安培极冠边界

摘要。高纬度大气是一个动态区域，其过程响应来自太阳、磁层、中性大气和电离层的强迫。从历史上看，磁层-电离层相互作用的主导地位促使高层大气研究在检查磁层-电离层-热层耦合过程时使​​用磁坐标。然而，极冠、极光卵形和极光卵形赤道内的主要相互作用之间存在显着差异。组织与这些边界相关的数据已被证明可以改善气候学和统计研究，但由于极光椭圆的变化性质以及测量其极地和赤道边界的困难，这样做的过程变得复杂。本研究提出了一组新的开放-封闭磁场线边界 (OCB)，这些边界是从活动磁层和行星电动力学响应实验 (AMPERE) 磁扰数据中获得的。AMPERE 对场对齐电流 (FAC) 的观测用于确定区域 1 (R1) 和区域 2 (R2) FAC 系统之间的边界位置。该当前边界被认为通常位于 OCB 赤道方向几度处，使其成为获取 OCB 位置的良好候选者。将 AMPERE R1-R2 边界与国防气象卫星计划专用传感器 J (DMSP SSJ) 电子能量通量边界进行比较，以检验该假设并确定 R1-R2 边界与 OCB 之间系统偏移的最佳估计值作为函数磁当地时间。这些校准的边界，以及从磁层顶到极光全球探索 (IMAGE) 观测的成像仪获得的 OCB，使用 DMSP 测量的对流反转边界的同时观测进行验证。验证表明，来自 IMAGE 和 AMPERE 的 OCB 可以在统计研究中一起使用，提供长期数据集的基础，可用于分离源自极冠内部和外部的观测。