The Empirical Canadian High Artic Ionospheric Model (E-CHAIM) provides the four-dimensional ionosphere electron density at northern high latitudes (>50° geomagnetic latitude). Despite its emergence as the most reliable model for high-latitude ionosphere density, there remain significant deficiencies in E-CHAIM's representation of the lower ionosphere (below ∼200 km) due to a sparsity of reliable measurements at these altitudes, particularly during energetic particle precipitation events. To address this deficiency, we have developed a precipitation component for E-CHAIM to be driven by satellite-based far-ultraviolet (FUV) imager data. Satellite observations of FUV emissions may be used to infer the characteristics of energetic particle precipitation and subsequently calculate the precipitation-enhanced ionization rates and ionosphere densities. In order to demonstrate the improvement of E-CHAIM's ionosphere density representation with the addition of a precipitation component, this paper presents comparisons of E-CHAIM precipitation-enhanced densities with ionosphere density measurements of three auroral region incoherent scatter radars (ISRs) and one polar cap ISR. Calculations for 29,038 satellite imager and ISR conjunctions during the years 2005–2019 revealed that the root-mean-square difference between E-CHAIM and ISR measurements decreased by up to 2.9 × 10¹⁰ ele/m³ (altitude dependent) after inclusion of the precipitation component at auroral sites, and by 2.6 × 10⁹ ele/m³ in the polar cap. Improvements were most substantial in the winter season and during active auroral conditions. The sensitivity of precipitation-enhanced densities to uncertainties inherent to the calculation method was also examined, with the bulk of the errors due to uncertainties in FUV imager data and choice of distribution function for precipitation energy spectra.

中文翻译：

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加拿大高北极电离层经验模型降水增强密度的开发和验证

加拿大高北纬电离层实证模型 (E-CHAIM) 提供了北高纬度地区（地磁纬度 > 50°）的四维电离层电子密度。尽管 E-CHAIM 作为高纬度电离层密度最可靠的模型出现，但由于在这些高度缺乏可靠的测量，尤其是在高能粒子降水期间，E-CHAIM 对低电离层（约 200 公里以下）的表示仍然存在重大缺陷事件。为了解决这一缺陷，我们为 E-CHAIM 开发了一个降水组件，由基于卫星的远紫外 (FUV) 成像仪数据驱动。FUV 发射的卫星观测可用于推断高能粒子降水的特征，并随后计算降水增强的电离率和电离层密度。为了证明 E-CHAIM 的电离层密度表示增加了降水分量的改进，本文介绍了 E-CHAIM 降水增强密度与三个极光区非相干散射雷达 (ISR) 和一个极地的电离层密度测量结果的比较。上限 ISR。对 2005-2019 年间 29,038 个卫星成像仪和 ISR 连接点的计算表明，E-CHAIM 和 ISR 测量值之间的均方根差减少了 2.9 × 10 s 电离层密度表示加上降水分量，本文介绍了 E-CHAIM 降水增强密度与三个极光区非相干散射雷达 (ISR) 和一个极冠 ISR 的电离层密度测量值的比较。对 2005-2019 年间 29,038 个卫星成像仪和 ISR 连接点的计算表明，E-CHAIM 和 ISR 测量值之间的均方根差减少了 2.9 × 10 s 电离层密度表示加上降水分量，本文介绍了 E-CHAIM 降水增强密度与三个极光区非相干散射雷达 (ISR) 和一个极冠 ISR 的电离层密度测量值的比较。对 2005-2019 年间 29,038 个卫星成像仪和 ISR 连接点的计算表明，E-CHAIM 和 ISR 测量值之间的均方根差减少了 2.9 × 10¹⁰  ele/m ³（取决于海拔高度）在极光站点包含降水分量后，在极冠中增加 2.6 × 10 ⁹  ele/m ³。在冬季和活跃的极光条件下，改善最为显着。还研究了降水增强密度对计算方法固有的不确定性的敏感性，其中大部分误差是由于 FUV 成像仪数据的不确定性和降水能谱分布函数的选择造成的。