An Updated Model Providing Long-Term Data Sets of Energetic Electron Precipitation, Including Zonal Dependence
An Updated Model Providing Long-Term Data Sets of Energetic Electron Precipitation, Including Zonal Dependence
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提供高能电子沉淀长期数据集（包括区域依赖性）的更新模型
DOI：
10.1029/2017jd028253
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Van De Kamp M
中科院分区：
文献类型：
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作者：
Van De Kamp M
在这项研究中，来自低地球轨道国家海洋和大气管理局和MetOp极地轨道环境卫星的30至1,000 keV高能电子沉淀（EEP）数据以两种改进的方式处理，与之前的研究相比。首先，所有受噪声影响的数据都被更仔细地删除，以便在地磁安静时期提供更真实的低通量表示。其次，根据影响降水通量特征的重要因素磁地方时（MLT）对数据进行分析。我们开发了一个改进的纬向平均EEP模型和一个依赖于MLT的新模型，它们都能更好地模拟安静时间的低通量。模型提供了假设幂律梯度的EEP谱。利用时间分辨率为1天的地磁指数，给出了谱参数作为壳值相对于等离子体顶的函数。模式的结果与1998-2012年期间的EEP观测结果比较良好。对MLT相关数据的分析发现，在磁安静时期，EEP通量集中在当地午夜附近。随着扰动水平的增加，在所有MLT上的通量都增加。在扰动时期，通量在黎明部分最强，在傍晚部分最弱。MLT依赖模型模拟了这种行为。这些模型的结果可用于产生任何时期的电离率数据集，这些时期的地磁指数是可用的（记录或预测的）。该电离率数据集将能够模拟EEP对大气和气候的影响，并具有实际的EEP变率。
In this study 30‐ to 1,000‐keV energetic electron precipitation (EEP) data from low Earth orbiting National Oceanic and Atmospheric Administration and MetOp Polar Orbiting Environmental Satellites were processed in two improved ways, compared to previous studies. First, all noise‐affected data were more carefully removed, to provide more realistic representations of low fluxes during geomagnetically quiet times. Second, the data were analyzed dependent on magnetic local time (MLT), which is an important factor affecting precipitation flux characteristics. We developed a refined zonally averaged EEP model, and a new model dependent on MLT, which both provide better modeling of low fluxes during quiet times. The models provide the EEP spectrum assuming a power law gradient. Using the geomagnetic indexApwith a time resolution of 1 day, the spectral parameters are provided as functions of theLshell value relative to the plasmapause. Results from the models compare well with EEP observations over the period 1998–2012. Analysis of the MLT‐dependent data finds that during magnetically quiet times, the EEP flux concentrates around local midnight. As disturbance levels increase, the flux increases at all MLT. During disturbed times, the flux is strongest in the dawn sector and weakest in the late afternoon sector. The MLT‐dependent model emulates this behavior. The results of the models can be used to produce ionization rate data sets over any time period for which the geomagneticApindex is available (recorded or predicted). This ionization rate data set will enable simulations of EEP impacts on the atmosphere and climate with realistic EEP variability.