Land use Changes and Mineral Dust Emission in Central and East Asia: the Role of Model's Spatial Resolution

The vast arid and semi-arid regions of Northern Eurasia are the world's largest sources of atmospheric mineral dust. Over the past century human-induced changes in land use resulted in the expansion of dust sources likely causing an additional dust burden (called anthropogenic dust). Reliable assessment of the anthropogenic component of mineral dust is needed to improve the understanding of climate change in this region. Practically all previous studies (including IPCC, 2001) relied on the general circulation models (GCMs) to predict dust emission from the natural and anthropogenic sources, although it has been demonstrated that the GCM coarse resolution hampers the realistic simulation of dust entrainment processes. Here we examine how the selection of model spatial resolution affects the dust emission and implications to the assessment of anthropogenic dust in the Aral Sea and Gobi-Taklamakan regions. A series of modeling experiments has been conducted with the PSU/NCAR Mesoscale Model MM5 coupled with dust production schemes at different spatial model grids ranging from 10 km to 200 km. The effects of spatial averaging for individual dust sources with different topography, vegetation cover, surface soil properties and erodibility were investigated. By relating dust modeling to ground-based and satellite observations, we attempt to identify the appropriate temporal and spatial resolution for adequate intercomparison between model results and observational data.