Insulation of Dust and Water Vapor by Martian Hadley Circulation

Dust and water vapor are key components influencing radiative processes in the Martian atmosphere. We identify a distinct barrier mechanism driven by the planetary-scale Hadley circulation (HC), which plays a significant role in controlling the global spatial distribution of dust and water vapor. Using six years of output data from the Ensemble Mars Atmosphere Reanalysis System (EMARS), we analyze the behavior of these components during northern winter. Our results reveal contrasting spatial patterns: dust is predominantly confined within the HC, while water vapor accumulates outside it. This differentiation is attributed to the distinct source regions of dust and water vapor. We demonstrate that the HC not only constrains these source regions but also acts as a barrier to their mixing. These findings highlight the critical role of HC dynamics in modulating the distribution of dust and water vapor in the Martian atmosphere and provide new insights into the complexity of Martian material cycle.