一种适合MSNA区域的单站TEC经验模型:以ohi3站为例

A Single-Station Empirical TEC Model Suitable for MSNA Area: Taking ohi3 Station as an Example

  • 摘要: 中纬度夏季夜间异常(midlatitude summer nighttime anomaly, MSNA)区域内的总电子含量(total electron content, TEC)的日变特性存在季节性差异,能否有效描述MSNA的特征是检验电离层TEC经验模型精度的关键指标之一。针对MSNA现象,提出了一种适合MSNA区域的单站电离层TEC经验模型,命名为SSM-T2(single station model type2)模型;以位于MSNA区域内的南极半岛上的奥伊金斯站(ohi3)为例,验证了该模型的有效性。SSM-T2模型由3部分组成,分别是TEC日变化分量、季节变化分量和随太阳活动分量,模型中的系数由非线性最小二乘拟合得到。在南极半岛的ohi3站上,模型拟合测试结果表明,SSM-T2-ohi3模型与建模数据GPS-TEC拟合得很好,较好地描述了MSNA现象。通过模型对比分析发现,在外推时间点上,SSM-T2-ohi3与CODE GIMs、SSM-month模型符合得很好,能有效描述MSNA的特征,具有较好的预测能力,且总体上优于IRI2016模型。

     

    Abstract: The diurnal variability of total electron content (TEC) in midlatitude summer nighttime anomaly (MSNA) region varies seasonally. Whether the characteristics of MSNA can be effectively described is one of the key indicators to test the accuracy of ionospheric empirical TEC model. A new ionospheric empirical TEC model named SSM-T2 (single station model type2) is proposed for MSNA anomalies. The effectiveness of the model is verified by an example of ohi3 located in the Antarctic Peninsula in the MSNA region. The SSM-T2 model consists of three parts: The diurnal variation component of TEC, the seasonal variation component and the solar activity component. The coefficients in the model are obtained by least square fitting. At the ohi3 station in the Antarctic Peninsula, test results of the model fitting show that the SSM-T2-ohi3 model fits well with the modeling data GPS-TEC, and describes the MSNA phenomenon well. By comparing and analyzing the models, it is found that SSM-T2-ohi3 is in good agreement with CODE GIMs (Center for Orbit Determination in Europe, Global Ionosphere Maps) and SSM-month models at extrapolated time points. It can effectively describe the characteristics of MSNA and has better prediction ability than IRI2016 model.

     

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