Abstract The Mars’ rotational rate, or equivalently its length-of-day (LOD), varies slightly due to global atmospheric changes. And the atmospheric dust cycle is considered to be one key process impacting the Mars’ atmosphere. Lewis and Barker (2005) demonstrated the close link of the semidiurnal tidal amplitude with the atmospheric dust content. In consideration of tidal effects in the Mars’ variable rotation, possible connection may exist between the Mars’ semidiurnal LOD amplitude variation and atmospheric dust cycles. In this study, the Mars’ LOD variations which are influenced by global atmosphere, and the atmospheric dust cycle index (ADCI) are computed based on eight realistic scenarios of the Martian Years (MY) 24–31 of the Martian Climate Database. The semidiurnal LOD amplitude change and the ADCI are found to be correlated at the 99% significance level, and they present similar time-varying wavelet spectral structures. In mature stages of global dust storms in MYs 25 and 28, relatively high LOD and ADCI values occurred synchronously across the time scales, ranging from a few months’ high frequency to seasonal and over one year’s lower frequency band. The close relation between the semidiurnal LOD amplitude variation and the ADCI reflects the strong coupling between the solid Mars and surficial atmosphere system, which relates primarily to the semidiurnal atmospheric tide.

中文翻译：

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火星半日LOD振幅变化与大气尘埃循环指数的相关性

摘要 由于全球大气变化，火星的自转速率或等效的日长（LOD）略有不同。大气尘埃循环被认为是影响火星大气的关键过程之一。Lewis 和 Barker (2005) 证明了半日潮汐振幅与大气尘埃含量之间的密切联系。考虑到火星可变自转的潮汐效应，火星半日LOD幅度变化与大气尘埃循环之间可能存在联系。在这项研究中，受全球大气影响的火星 LOD 变化和大气尘埃循环指数 (ADCI) 是基于火星气候数据库的火星年 (MY) 24-31 的八个现实场景计算的。发现半日 LOD 幅度变化和 ADCI 在 99% 的显着性水平上相关，并且它们呈现出相似的时变小波谱结构。在 MYs 25 和 28 的全球沙尘暴成熟阶段，相对较高的 LOD 和 ADCI 值在时间尺度上同步出现，从几个月的高频到季节性和一年以上的较低频段。半日LOD幅度变化与ADCI的密切关系反映了固体火星与地表大气系统之间的强耦合，主要与半日大气潮汐有关。范围从几个月的高频到季节性和一年以上的低频段。半日LOD幅度变化与ADCI的密切关系反映了固体火星与地表大气系统之间的强耦合，主要与半日大气潮汐有关。范围从几个月的高频到季节性和一年以上的低频段。半日LOD幅度变化与ADCI的密切关系反映了固体火星与地表大气系统之间的强耦合，主要与半日大气潮汐有关。