Temporal variability of dust mobilization and concentration in source regions

Abstract

The time‐varying properties of dust mobilization and concentration variability in source areas are studied in model simulations to understand the processes that control entrainment of dust into the atmosphere. Two different meteorological reanalysis data sets (National Centers for Environmental Prediction/National Center for Atmospheric Research and NASA Data Assimilation Office) and two different source parameterizations are used for the analysis, which is done for six different main dust source regions. The results show that ∼35–70% variance of dust mobilization is associated with diurnal variability of dust mobilization in the major dust sources regions, and this is similar using different meteorological analyses and source parameterizations. Synoptic‐scale variability is responsible for 6–50% of the dust mobilization, with more variation between different meteorology and parameterizations. The variability of dust concentrations in source regions is very sensitive to source meteorology and parameterization, with the synoptic variability responsible for 30–50% of the variability in some configurations or 6–40% in other configurations. Diurnal variability in concentrations varies from 20–50 to 25–80% depending on the model configuration. Analyses suggest that dust mobilization and dust concentration are more influenced by synoptic variability in Australia and east Asia than in North Africa and Arabian dust source regions, consistent with observations of cold fronts and cyclone movements systems driving dust mobilization and transport in Australia and east Asia source regions. Differences in variability between different meteorological data sets and source parameterizations suggest that possible dust feedbacks onto the dust cycle may be sensitive to source parameterization and model.