Modeling and Analysis of Long-Range Dust Transport from the Sahara and Arabian Deserts To West Asia Using WRF-Chem and Remote Sensing: Insights from the Spring 2015 Dust Event

This study investigates the transboundary dust transport from the Sahara and Arabian Deserts to West Asia during a major event in spring 2015. The analysis integrates satellite observations, ground-based PM₁₀ measurements, and simulations from the WRF-Chem model configured at a 10 × 10 km grid resolution. The model was coupled with the Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) dust emission scheme and employed the Four-Dimensional Data Assimilation (FDDA) technique. Model outputs were evaluated against in-situ PM₁₀ observations and satellite-derived aerosol data. Results indicate two distinct dust intrusion episodes: the first, originating from the Arabian Desert, affected northern Iraq and southeastern Türkiye on May 23–24; the second, associated with the Sahara Desert dust, arrived on May 27, merging with the earlier plume by May 28. This convergence led to elevated PM₁₀ concentrations, exceeding a daily mean of 500 µg/m³ across parts of West Asia. Aerosol observations confirmed substantial contributions from both desert sources, with Aerosol Optical Depth (AOD) values frequently reaching or exceeding 1.0 in several regions. These events were driven by strong Sahara-Arabian heating, which enhanced pressure gradients and generated Shamal winds and easterly surges, promoting dust uplift and long-range transport. Significant spatial variability was observed, from severe air pollution in some areas to minimal impacts elsewhere. During dust events, modeled–observed PM₁₀ correlations ranged 0.14–0.81 with systematic underestimation. These results highlight the need for improved dust emission parameterizations, early warning systems, and high-resolution regional models to better support air quality management and public health planning.