Dust transport pathways from The Great Basin

Abstract

The Great Basin is at risk of increased wind erosion and dust emissions due to grazing pressure, urbanization, wildfire, and non-native plant invasion. Recent efforts to quantify wind erosion risk on Great Basin rangelands identified high to extreme wind erosion and dust emission hotspots. However, the spatial extent and seasonal variability of dust transport pathways from the Great Basin, and thus the local and regional dust impacts, are not well understood. Here, we computed forward air-parcel trajectories using the Hybrid Single-Particle Lagrangian Integrated Trajectory model using the North American Regional Reanalysis 32-km meteorological data and kernel density analysis to describe potential seasonal dust transport pathways associated with three Great Basin wind erosion hotspots. Probability mass-densities for six different heights above ground level (AGL) were estimated to describe the spatial and vertical extent of potential dust transport across North America. A large proportion of trajectories occurred within 0 – 500 m AGL in spring (25.9 % − 32.7 %), fall (33.6 % − 35.1 %), and winter (44.1 % − 53.8 %). The proportion of trajectories at 2000 – 5000 m AGL is highest in summer (32.1 % − 39.8 %) and spring (23.0 % − 23.3 %). Thus, long range west-to-east transport of dust over North America is likeliest in summer. However, local redistribution of dust near hotspots, is more likely in spring, fall, and winter. This study helps to link potential dust transport pathways to wind erosion hotspots for mitigating the local and regional impacts of dust emissions, informing rangeland management strategies, and improving air quality assessments across North America.