Determining how global dust storms originate and develop is one of the major challenges of Martian meteorology. We model the 2018 global dust storm using the Ensemble Mars Atmosphere Reanalysis System (EMARS), combining satellite observations with a Mars global climate model via data assimilation. A reanalysis is a valuable data set for this investigation because it is anchored to the real Martian atmosphere by temperature and dust observations, and the model provides full 4D coverage of wind fields, which are not directly observed and are key to assessing advection. Dust was observed to encircle the northern hemisphere early on in the storm's development. This encirclement could be caused by either the formation of new lifting centers along the path of observed encirclement or the advection of dust from active lifting center(s) elsewhere. Results from EMARS, including particle advection from inferred EMARS winds, provide evidence that the aforementioned dust encircling Mars's northern hemisphere may come from the initial lifting center of the storm, near Chryse Planitia. We propose that dust from the initial lifting center of the storm was entrained into the Martian Hadley circulation, with the assistance of the thermal tides, and then entrained into the northern hemisphere westerly jet.

中文翻译：

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利用EMARS调查2018年全球沙尘暴中的尘埃包围火星

确定全球沙尘暴如何产生和发展是火星气象学的主要挑战之一。我们使用Ensemble Mars Atmosphere Reanalysis System（EMARS）对2018年全球沙尘暴进行建模，并通过数据同化将卫星观测结果与Mars全球气候模型相结合。重新分析对于这项研究是有价值的数据集，因为它通过温度和尘埃观测值被锚定到真实的火星大气中，并且该模型提供了风场的完整4D覆盖范围，这不是直接观察到的，并且是评估对流的关键。在风暴发展的早期，观测到尘埃环绕北半球。这种包围可能是由于沿观察到的包围形成的路径形成了新的举升中心，也可能是来自其他活动举升中心的粉尘对流。EMARS的结果，包括EMARS风的对流，提供了证据表明上述环绕火星北半球的尘埃可能来自Chryse Planitia附近风暴的最初起升中心。我们建议将风暴的最初提升中心的尘埃在热潮的帮助下带入火星哈德利环流，然后带入北半球西风急流。