Critical Thresholds for Lofting Dust in The Southwestern United States; A Modeling Approach.

Recent research has revealed that windblown dust is an impactful yet underappreciated weather hazard in the United States. Over a ten-year period, Tong et al. (2023) found that windblown dust caused more traffic fatalities than fire weather, hurricanes, and winter storms. This underscores the need for continued research and understanding of windblown dust processes, particularly the initiation of dust lofting, to improve forecasting and response. Dust lofting is a complex physical process that is challenging to model and primarily limited by datasets lacking critical parameters and robust validation. However, there remains an opportunity to establish critical threshold criteria for various meteorological and land surface parameters that contribute to dust lofting. The work herein will present an initial identification and thresholding of significant parameters for dust lofting in the southwestern United States using a numerical modeling approach. Collected cases of windblown dust are modeled using the Weather Research and Forecasting model with chemistry with the Air Force Weather Agency dust scheme and initialized with Modern-Era Retrospective analysis for Research and Applications, Version 2 reanalysis data. Investigated parameters include friction velocity, wind speed, soil moisture, green vegetation fraction, temperature, soil type, and relative humidity.