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Spiga, Aymeric and Lewis, Stephen R.
(2010).
DOI: https://doi.org/10.1555/mars.2010.0006
Abstract
Background: Mars si both a windy and dusty environment. Ariborne dust is a crucial climate component on Mars. It impacts atmospheric circulations at large-, meso- and micro-scales, which in turn control dust lifting from the surface and transport in the atmosphere. Dust lifting processes and feedbacks on atmospheric circulations are currently not well understood.
Method: Our purpose is to show how mesoscale models and large-eddy simulations help to explore small-scale circulation patterns which are potentially important for lifting dust into the atmosphere but which are unresolved by global climate models. We focus on variations of friction velocity, u*, relevant for dust lifting, in particular investigating maximum values and the spatial and temporal variability of u*.
Conclusion: Meteorological scales between 100 km and 10 km can be studied by high-resolution global circulation and limited-area mesoscale models, which both show strong topographic control of the daytime and nighttime near-surface winds. Scales below 10 km and 1 km are dominated by turbulent gusts and dust devils, two distinct convective boundary layer processes likely to lift dust from the surface. In low-latitude regions, boundary layer depth and friction velocity u* are correlated with surface altimetry. Further studies will be carried out to parameterize lifting by boundary layer processes and dust radiative effects once transported in the atmosphere.