From fine to giant: multi-instrument assessment of the dust particle size distribution at an emission source during the J-WADI field campaign

A groundbreaking study conducted during the J-WADI field campaign in Wadi Rum, Jordan, revealed that super-coarse and giant dust particles (diameter >10 µm) dominate the mass concentration of emitted dust, accounting for approximately 90% of total mass. This finding challenges previous assumptions about dust particle size distributions at emission sources, emphasizing the significant role of these larger particles in climate interactions. The research utilized a multi-instrument approach, combining aerosol spectrometers with overlapping size ranges to systematically validate and characterize particle sizes from 0.4 µm to 200 µm. Results showed that dust concentrations and the abundance of super-coarse particles increased with friction velocity (u*) above 0.22 m/s, particularly under neutral to unstable atmospheric conditions. Physical samples collected confirmed the derived particle size distributions, despite challenges posed by instrument sensitivity at larger sizes.

Meyer, H., Kandler, K., Dupont, S., Escribano, J., Girdwood, J., Nikolich, G., Alastuey, A., Etyemezian, V., González-Flórez, C., González-Romero, A., Hussein, T., Irvine, M., Knippertz, P., Möhler, O., Querol, X., Stopford, C., Vogel, F., Weis, F., Wieser, A., et al. (2026). From fine to giant: multi-instrument assessment of the dust particle size distribution at an emission source during the J-WADI field campaign. Atmospheric Measurement Techniques, 19(1), 21–61. https://doi.org/10.5194/amt-19-21-2026