In recent years, significant progress has been in ionospheric modeling research through data ingestion and data assimilation from a variety of sources, including ground-based global navigation satellite systems, space-based radio occultation and satellite altimetry (SA). Given the diverse observing geometries, vertical data coverages and intermission biases among different measurements, it is imperative to evaluate their absolute accuracies and estimate systematic biases to determine reasonable weights and error covariances when constructing ionospheric models. This study specifically investigates the disparities among the vertical total electron content (VTEC) derived from SA data of the Jason and Sentinel missions, the integrated VTEC from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) and global ionospheric maps (GIMs). To mitigate the systematic bias resulting from differences in satellite altitudes, the vertical ranges of various VTECs are mapped to a standardized height. The results indicate that the intermission bias of SA-derived VTEC remains relatively stable, with Jason-1 serving as a benchmark for mapping other datasets. The mean bias between COSMIC and SA-derived VTEC is minimal, suggesting good agreement between these two space-based techniques. However, COSMIC and GIM VTEC exhibit remarkable seasonal discrepancies, influenced by the solar activity variations. Moreover, GIMs demonstrate noticeable hemispheric asymmetry and a degradation in accuracy ranging from 0.7 to 1.7 TECU in the ocean-dominant Southern Hemisphere. While space-based observations effectively illustrate phenomena such as the Weddell Sea anomaly and longitudinal ionospheric characteristics, GIMs tend to exhibit a more pronounced mid-latitude electron density enhancement structure.

近年来，通过从各种来源（包括地面全球导航卫星系统、天基无线电掩星和卫星测高（SA））获取数据和同化数据，电离层建模研究取得了重大进展。鉴于不同测量之间的观测几何形状、垂直数据覆盖范围和间歇偏差的不同，在构建电离层模型时，必须评估其绝对精度并估计系统偏差，以确定合理的权重和误差协方差。这项研究专门调查了来自 Jason 和 Sentinel 任务的 SA 数据的垂直总电子含量 (VTEC)、来自气象、电离层和气候星座观测系统 (COSMIC) 的综合 VTEC 以及全球电离层地图 (GIM) 之间的差异。为了减轻卫星高度差异造成的系统偏差，各种 VTEC 的垂直范围被映射到标准化高度。结果表明，SA 衍生的 VTEC 的间歇偏差保持相对稳定，Jason-1 可以作为绘制其他数据集的基准。 COSMIC 和 SA 衍生的 VTEC 之间的平均偏差很小，表明这两种天基技术之间具有良好的一致性。然而，受太阳活动变化的影响，COSMIC 和 GIM VTEC 表现出显着的季节性差异。此外，在以海洋为主的南半球，GIM 表现出明显的半球不对称性，精度下降了 0.7 到 1.7 TECU。 虽然天基观测有效地说明了威德尔海异常和纵向电离层特征等现象，但 GIM 往往表现出更明显的中纬度电子密度增强结构。