Quantifying the anthropogenic dust emission from agricultural land use and desiccation of the Aral Sea in Central Asia

Abstract

AbstractA regional dust model system is applied to quantify the anthropogenic dust emission in the post‐Soviet Central Asia from 2000 to 2014. Two physically based dust schemes suggest that a proportion of 18.3–32.8% of total dust emissions is contributed by agricultural land use and the desiccation of Aral Sea, whereas a simplified dust scheme yields higher estimates in the range of 49.7–56.5% depending on whether a static or dynamic preferential dust source function is used. The dust schemes also differ greatly in the spatial distribution of anthropogenic dust and the sensitivity to the use of land use intensity in separating natural and human‐made source areas, suggesting that the model representation of erosion threshold velocity, especially the role of vegetation, is a key source of model uncertainty in quantifying anthropogenic dust. The relative importance of agriculture and dried Aral Sea bed (Aralkum) differs greatly among the dust schemes. Despite the increased dust from the expansion of Aralkum, there is a negative trend in the anthropogenic dust proportion, indicating a shift of dust emission toward natural source areas. All dust schemes show a decrease in anthropogenic dust in response to land cover changes over agricultural lands.