Quantifying the Wind-Lens Effect on Dust Emission From the Bodélé Depression

The Bodélé Depression is the world's most intense dust source. One proposed explanation is wind amplification through an upwind mountain pass, the “wind-lens” effect, reflecting a Venturi-type acceleration. Using over 20 years of ERA5 reanalysis 10 m winds at the pass entrance and exit, together with Moderate Resolution Imaging Spectroradiometer Aerosol Optical Depth at the Bodélé, we show that winds nearly double as they traverse the pass. Two distinct dust-emission regimes emerge, separated by an exit-wind speed of ∼8 m/s. Under weaker winds, dust loading is low and largely independent of speed, while stronger winds produce sharply increasing dust and more aligned entrance–exit flow. These regimes coincide with seasonal shifts: weak, variable summer winds contrast with a stronger, directionally aligned winter regime when dust events are frequent. The strongest emissions occur when exit winds cluster near 48° and entrance winds have a northern component, reflecting optimal alignment with the corridor.