Global dust model intercomparison in AeroCom phase I

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Huneeus, N., Schulz, M., Balkanski, Y., Griesfeller, J., Krol, M.C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2011
• Subjects: aerosol direct; atmospheric iron deposition; general-circulation model; goddard-institute; last glacial maximum; mineral dust; north-atlantic; optical-properties; sulfur cycle; tropospheric chemistry; North Atlantic
• Online Access: https://research.wur.nl/en/publications/global-dust-model-intercomparison-in-aerocom-phase-i; https://doi.org/10.5194/acp-11-7781-2011

This study presents the results of a broad intercomparison of a total of 15 global aerosol models within the AeroCom project. Each model is compared to observations related to desert dust aerosols, their direct radiative effect, and their impact on the biogeochemical cycle, i.e., aerosol optical depth (AOD) and dust deposition. Additional comparisons to Angström exponent (AE), coarse mode AOD and dust surface concentrations are included to extend the assessment of model performance and to identify common biases present in models. These data comprise a benchmark dataset that is proposed for model inspection and future dust model development. There are large differences among the global models that simulate the dust cycle and its impact on climate. In general, models simulate the climatology of vertically integrated parameters (AOD and AE) within a factor of two whereas the total deposition and surface concentration are reproduced within a factor of 10. In addition, smaller mean normalized bias and root mean square errors are obtained for the climatology of AOD and AE than for total deposition and surface concentration. Characteristics of the datasets used and their uncertainties may influence these differences. Large uncertainties still exist with respect to the deposition fluxes in the southern oceans. Further measurements and model studies are necessary to assess the general model performance to reproduce dust deposition in ocean regions sensible to iron contributions. Models overestimate the wet deposition in regions dominated by dry deposition. They generally simulate more realistic surface concentration at stations downwind of the main sources than at remote ones. Most models simulate the gradient in AOD and AE between the different dusty regions. However the seasonality and magnitude of both variables is better simulated at African stations than Middle East ones. The models simulate the offshore transport of West Africa throughout the year but they overestimate the AOD and they transport too fine particles. ...