Pioneer Venus Orbiter radio occultations of the Venus atmosphere in direct comparison with Venus Express VeRa and Akatsuki radio occultations

金星快车上的无线电科学实验VeRa在2007年至2014年期间通过无线电波探测了金星的大气层和电离层，并提供了迄今为止最大的金星无线电掩星集，包括900个温度，压力，中性数密度和电子密度分布。另一个大型数据集是由先锋金星轨道器（PVO）无线电掩星实验（PVO ORO）从1978年到1988年提供的。然而，PVO ORO配置文件在公共档案中不容易获得，但NASA深空网络天线记录的原始数据文件以二进制可读数据格式存在。我们建议使用现代软件例程重新处理这些原始PVO ORO数据文件，实际上用于金星快车和火星快车的日常工作，以便处理，存档，并因此保存这些PVO ORO更高的科学数据产品，以备将来使用。 重要的科学目标是直接比较在最强的太阳周期之一期间观测到的PVO ORO剖面与在当前相对较弱的太阳周期期间观测到的VEX-VeRa和Akatsuki剖面，以揭示中性大气温度、硫酸气体吸收率和电离层电子密度的长期变化。首次尝试表明，通过使用新处理的更加准确的PVO轨道文件，可以显著降低PVO ORO剖面的高度不确定性，这本身就证明了重新处理的合理性，以便为后代保存这一宝贵的科学数据集。我们目前是这个星球上唯一一个有能力和经验的团队，可以进行这种再处理和充分利用这个特殊的数据集。

The radio science experiment VeRa on Venus Express sounded the atmosphere and ionosphere of Venus from 2007 to 2014 by radio waves and provided the largest Venusian radio occultation set of 900 temperature, pressure, neutral number density and electron density profiles, respectively, to date. Another large data set was provided by the Pioneer Venus Orbiter (PVO) radio occultation experiment (PVO ORO) from 1978 to 1988. The PVO ORO profiles, however, are not or not easily available in public archives, but the raw data files recorded by The NASA Deep Space Network antennas, in a binary readable data format, are.We propose to reprocess these raw PVO ORO data files with modern software routines, actually used for Venus Express and Mars Express in daily routine, in order to process, archive, and therefore preserve these PVO ORO higher science data products for the future. Important scientific objectives are the direct comparison of the PVO ORO profiles observed during one of the strongest solar cycles with those from VEX-VeRa and Akatsuki, observed during the current relatively weak solar cycle, to reveal long term changes in neutral atmosphere temperature, in absorptivity by gaseuos H2SO4, and in ionospheric electron density. First attempts have shown that the altitude uncertainty of the PVO ORO profiles can be reduced significantly by using the newly processed and much more accurate PVO orbit file which by itself would justify a reprocessing to preserve this valuable scientific data set for future generations. We are currently the only team on this planet able and experienced for this reprocessing and the full exploitation of this special data set.