The dayside structures of the ionospheres of Mars and Venus: Comparison and interpretation of results from a fast and flexible model with actual day-to-day observations

无线电科学实验火星快车无线电科学、火星全球勘测者无线电科学和金星快车无线电科学分别提供了火星和金星电离层昼侧电子密度分布的巨大数据库。在最初提议的时间范围内，推导出了剖面特征/环境参数，并为火星（中性大气：火星气候数据库）和金星（中性大气：金星大气）开发了一个快速、灵活的电离层电子密度（艾奥纳-1）不受时间影响的光化学模型。MaRS和VeRa观测和模拟的电离层主峰（M2/V2）参数的比较给出了火星的极好的全球一致性，但不是金星（不切实际的金星中性大气，Peter等人，2014年）。然而，个别M2/V2的高度和宽度的详细协议是必要的额外的小尺度功能的建模。匹配观测和模式主峰高度/宽度表明，在观测期间，真实的和模式中性大气之间近似一致。为了模拟次级层M1/V1以下的流星层，结合流星层模型（艾奥纳/MSDM）对适当的MaRS剖面进行了个案研究。MSDM考虑了Mg和Fe在大气中的沉积，并计算了通过光电离/电荷交换形成的金属离子。另外还开发了一个电离层高度中性大气一维流体静力学模型，作为在电离层高度建立更灵活的中性大气的起点，采用小比例高度网格，将电离艾奥纳高度模型的适用性扩大到更大的观测数据集。艾奥纳-1已升级为具有复杂反应方案的随时间变化的光化学模型（艾奥纳-2），以得出关于电离层离子密度的结果。扩展提案将把NIA和艾奥纳-2结合起来，以便更详细地了解火星和金星电离层高度电离层与中性大气之间的相互作用。无线电科学低中性大气观测几乎与电离层观测同时进行，并为NIA提供现实的初步猜测中性密度。用自洽的中性、离子和电子温度计算耦合的中性大气/电离层将（a）覆盖主峰M2/V2以上的电离层顶侧的输运区，（B）产生M1/V1以下异常形成的更现实的计算，（c）评估M1/V1/M2/V2内二次电离的贡献，（d）解释神秘的隆起，电子在顶侧不成比例地积累，以及（e）提供无线电科学观测期间电离层高度中性大气的可能状态。最后一点对于全球环流模式的发展将是非常有用的，特别是对于金星，在这个高度范围内的数据情况很差。

The radio science experiments Mars Express Radio Science, Mars Global Surveyor Radio Science and Venus Express Radio science delivered a huge database of the ionospheric dayside electron density distribution of Mars and Venus, respectively. During the original proposal time frame, profile characteristics/environmental parameters were derived and a fast and flexible time-independent photochemical model of the ionospheric electron density (IonA-1) was developed for Mars (neutral atmosphere: Mars Climate Database) and Venus (neutral atmosphere: VenusGRAM). The comparison of MaRS and VeRa observed and modeled ionospheric main peak (M2/V2) parameters gave an excellent global agreement for Mars, but not for Venus (unrealistic VenusGRAM neutral atmosphere, Peter et al., 2014). However, a detailed agreement of the individual M2/V2 altitudes and widths is necessary for the modeling of additional small scale features. Matching observation and model main peak altitudes/widths indicate an approximate agreement between real and model neutral atmosphere during the time of observation. For the modeling of meteor layers below the secondary layer M1/V1, case studies for suitable MaRS profiles have been conducted in combination with a model for meteor layers (IonA/MSDM). MSDM considers the deposition of Mg and Fe into an atmosphere and computes the formation of metallic ions by photoionization/charge exchange. An additional 1D hydrostatic model of the neutral atmosphere at ionospheric altitudes (NIA) has been developed as a starting point for a more flexible neutral atmosphere at ionospheric heights with a small scale altitude grid to expand the applicability of IonA to a larger observational data set. IonA-1 has been upgraded into a time-dependent photo-chemical model with a complex reaction scheme (IonA-2) to yield results on ionospheric ion densities. The extended proposal shall couple NIA and IonA-2 to derive a more detailed understanding of the interaction between ionospheres and neutral atmospheres at ionospheric heights of Mars and Venus. The radio science lower neutral atmospheric observations are conducted almost concomitantly with the ionospheric observations and yield realistic first guess neutral densities for NIA. The computation of the coupled neutral atmosphere/ ionosphere with self-consistent neutral, ion and electron temperatures will (a) cover the transport regions of the ionospheric top-sides above the main peaks M2/V2, (b) yields a more realistic computation of the anomaly formation below M1/V1, (c) assess the contribution of secondary ionization within M1/V1/M2/V2, (d) explain the enigmatic bulge, a disproportionate accumulation of electrons in the topside and (e) provide possible states of the neutral atmosphere at ionospheric heights during the radio science observations. The last point will be very useful for the development of global circulation models, especially for Venus, where the data situation in this altitude range is poor.