Using the data sets of Mars Atmosphere and Volatile EvolutioN and OMNI for the period 2014 October 10–2020 February 14 and the heliocentric distance of 1–1.66 au, we investigate the statistical properties of solar wind upstream of Mars for the first time. The key parameters, including interplanetary magnetic field (IMF), proton density (N), bulk velocity (∣ V ∣), and dynamic pressure (P _dyn), are surveyed with regard to variations of solar activity level and heliocentric distance. We find that the parameters ∣IMF∣, N, and P _dyn monotonously decrease with heliocentric distance. Both ∣IMF∣ and P _dyn are generally stronger at a higher solar activity level (F _10.7 ≥ 70 sfu), while such activity has little relevance to N. In contrast, ∣ V ∣ basically keeps a median of about 370 km s⁻¹ and is insensitive to the solar activity level and heliocentric distance. We also find that the IMF upstream of Mars at the higher solar activity level has a much smaller spiral angle in the inward sector; thus, IMF seems “straighter” than that in the outward sector, although that is not so for the inward sector of the upstream of Earth. Our statistical survey can be used as a reference for upstream solar wind of Mars at 1.4 ∼ 1.7 au, and could benefit the studies on solar wind as well as the Martian space environment.

利用2014年10月10日至2020年2月14日期间火星大气和挥发性演化和OMNI的数据集以及1-1.66 au的日心距，我们首次研究了火星上游太阳风的统计特性。的关键参数，包括星际磁场（IMF），质子密度（Ñ），散速度（| V |），和动态压力（P_达因），是调查关于太阳活动水平和日心距的变化。我们发现参数∣IMF∣、N和P _dyn随日心距离单调减小。∣IMF∣ 和P _dyn 通常在较高的太阳活动水平（F _10.7 ≥ 70 sfu）时更强，而这种活动与N几乎没有相关性。相比之下，∣ V ∣ 基本上保持中位数在 370 km s ^-1左右，对太阳活动水平和日心距离不敏感。我们还发现，在较高太阳活动水平的火星上游的 IMF 在向内扇区具有更小的螺旋角；因此，IMF 似乎比向外部门的“直”，尽管地球上游的向内部门并非如此。我们的统计调查可以作为火星上游1.4∼1.7 au太阳风的参考，对太阳风和火星空间环境的研究有益。