The seasonal distribution of water vapor on Mars and its potential association with dust are investigated in this study. Observations obtained from the Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) reveal a hemispheric imbalance, with higher water vapor levels observed in the northern hemisphere during summer compared to the southern hemisphere. This observation suggests a tendency for water vapor accumulation towards the northern polar region, a phenomenon known as the Clancy effect. The primary contributing factors to this asymmetry include the Clancy effect and topographical variations, with higher elevations in the southern hemisphere and lower elevations in the northern hemisphere.However, dust storms represent the most prominent and asymmetric weather phenomenon on Mars. It is hypothesized that dust storms also influence the seasonal asymmetry of water vapor. To explore the impact of dust on the cross-equatorial transport of water vapor, simulations were conducted using the LMD Global Circulation Model (GCM). By modifying the global optical thickness of dust throughout the year to simulate near-dust-free conditions, we examined atmospheric wind fields, temperature patterns, and water vapor transport calculations. The results of our study demonstrate that dust amplifies the Hadley circulation, thereby facilitating further northward accumulation of water vapor in the northern hemisphere. Furthermore, the presence of dust alters the annual transport pattern of water vapor, transforming its unimodal distribution into a bimodal distribution. Additional investigations reveal that the influence of dust on water vapor uplift and cloud formation height outweighs its impact on large-scale circulation.The findings from this study significantly contribute to advancing our understanding of the intricate interactions between dust storms and the distribution of water vapor in the Martian atmosphere. This research sheds light on the factors that shape the atmospheric dynamics of the planet, thereby enriching our knowledge of Mars' climate system.


 

火星,沙尘,水