Imaging the topside ionosphere and plasmasphere with ionospheric tomography using COSMIC GPS TEC
Imaging the topside ionosphere and plasmasphere with ionospheric tomography using COSMIC GPS TEC
复制标题
DOI：
10.1002/2015ja021561
复制
发表时间：
2016-01
期刊：
影响因子：
--
通讯作者：
Talini Pinto Jayawardena;A. Chartier;P. Spencer;C. Mitchell
中科院分区：
文献类型：
--
作者：
Talini Pinto Jayawardena;A. Chartier;P. Spencer;C. Mitchell
基于GPS的电离层层析成像是一种众所周知的技术，用于成像GPS卫星和接收器之间的总电子含量（TEC）。然而，作为电子浓度的整体测量，TEC通常包括电离层和等离子层，由于电离层占主导地位，掩盖了来自上层电离层-等离子层的特征。成像这些区域需要一种技术来隔离顶层电离层-等离子层中的TEC。多仪器数据分析系统（MIDAS）采用层析成像技术对电离层中的电子分布进行成像。由于电离层以上存在不同的动力学，它在其他区域的实施还有待观察。本文讨论了MIDAS的扩展，使用基于GPS相位的TEC测量对这些高度进行成像，并遵循了Spencer和Mitchell（2011）的工作。等离子体受欧拉势描述的偶极子场线的约束，导致在地磁赤道周围对称分布。Gallagher等人（1988）对经验等离子体模型进行了模拟，通过将模拟重建与经验模型进行比较来验证该技术。星座气象、电离层和气候观测系统（COSMIC）被用作GPS接收器位置。在验证之后，对改进的MIDAS算法进行验证，其中从COSMIC GPS相位测量中重建了该地区的TEC，并与先前使用Jason‐1和COSMIC数据的研究进行了定性比较。结果表明，MIDAS可以成功成像其他研究中观测到的上层电离层-等离子层的特征/趋势，但绝对TEC的偏差归因于数据集性质和图像分辨率的差异。
GPS‐based ionospheric tomography is a well‐known technique for imaging the total electron content (TEC) between GPS satellites and receivers. However, as an integral measurement of electron concentration, TEC typically encompasses both the ionosphere and plasmasphere, masking signatures from the topside ionosphere‐plasmasphere due to the dominant ionosphere. Imaging these regions requires a technique that isolates TEC in the topside ionosphere‐plasmasphere. Multi‐Instrument Data Analysis System (MIDAS) employs tomography to image the electron distribution in the ionosphere. Its implementation for regions beyond is yet to be seen due to the different dynamics present above the ionosphere. This paper discusses the extension of MIDAS to image these altitudes using GPS phase‐based TEC measurements and follows the work by Spencer and Mitchell (2011). Plasma is constrained to dipole field lines described by Euler potentials, resulting in a distribution symmetrical about the geomagnetic equator. A simulation of an empirical plasmaspheric model by Gallagher et al. (1988) is used to verify the technique by comparing reconstructions of the simulation with the empirical model. The Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) is used as GPS receiver locations. The verification is followed by a validation of the modified MIDAS algorithm, where the regions' TEC is reconstructed from COSMIC GPS phase measurements and qualitatively compared with previous studies using Jason‐1 and COSMIC data. Results show that MIDAS can successfully image features/trends of the topside ionosphere‐plasmasphere observed in other studies, with deviations in absolute TEC attributed to differences in data set properties and the resolution of the images.