Satellites reveal Earth's seasonally shifting dust emission sources

作者：Adrian Chappell, Nicholas P. Webb, Mark Hennen, Kerstin Schepanski, Philippe Ciais, Yves Balkanski, Charles S. Zender, Ina Tegen, Zhenzhong Zeng, Daniel Tong, Barry Baker, Marie Ekström, Matthew Baddock, Frank D. Eckardt, Tarek Kandakji, Jeffrey A. Lee, Mohamad Nobakht, Johanna von Holdt, John Leys · 发表于：The Science of The Total Environment · 年份：2023 · DOI：10.1016/j.scitotenv.2023.163452 · 被引用次数：37 · 研究领域：Atmospheric aerosols and clouds、Aeolian processes and effects、Atmospheric chemistry and aerosols

Establishing mineral dust impacts on Earth's systems requires numerical models of the dust cycle. Differences between dust optical depth (DOD) measurements and modelling the cycle of dust emission, atmospheric transport, and deposition of dust indicate large model uncertainty due partially to unrealistic model assumptions about dust emission frequency. Calibrating dust cycle models to DOD measurements typically in North Africa, are routinely used to reduce dust model magnitude. This calibration forces modelled dust emissions to match atmospheric DOD but may hide the correct magnitude and frequency of dust emission events at source, compensating biases in other modelled processes of the dust cycle. Therefore, it is essential to improve physically based dust emission modules. Here we use a global collation of satellite observations from previous studies of dust emission point source (DPS) dichotomous frequency data. We show that these DPS data have little-to-no relation with MODIS DOD frequency. We calibrate the albedo-based dust emission model using the frequency distribution of those DPS data. The global dust emission uncertainty constrained by DPS data (±3.8 kg m−2 y−1) provides a benchmark for dust emission model development. Our calibrated model results reveal much less global dust emission (29.1 ± 14.9 Tg y−1) than previous estimates, and show seasonally shifting dust emission predominance within and between hemispheres, as opposed to a persistent North African dust emiss...