Global dust model intercomparison in AeroCom phase I

• Main Authors: Huneeus, N, Schulz, M, Balkanski, Y, Griesfeller, J, Kinne, S, Prospero, J, Bauer, S, Boucher, O, Chin, M, Dentener, F, Diehl, T, Easter, R, Fillmore, D, Ghan, S, Ginoux, P, Grini, A, Horowitz, L, Koch, D, Krol, M, Landing, W, Liu, X, Mahowald, N, Miller, R, Morcrette, J, Myhre, G, Penner, J, Perlwitz, J, Stier, P, Takemura, T, Zender, C
• Other Authors: Union, European Geosciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2016
• Subjects: Physics; Atmospheric,Oceanic,and Planetary physics; Arid environmental systems; Environment; Pacific; Indian; Antarc*; Antarctica; ice core
• Online Access: https://doi.org/10.5194/acpd-10-23781-2010; https://ora.ox.ac.uk/objects/uuid:0809989f-80b6-4c5e-8c17-c257a06424fd

Desert dust plays an important role in the climate system through its impact on Earth's radiative budget and its role in the bigeochemical cycle as a source of iron in high-nutrient-low-chlorophyll regions. A large degree of diversity exists between the many global models that simulate the dust cycle to estimate its impact on climate. We present the results of a broad intercomparison of a total of 15 global aerosol models within the AeroCom project. Each model is compared to observations focusing on variables responsible for the uncertainties in estimating the direct radiative effect and the dust impact on the bigeochemical cycle, i.e., aerosol optical depth (AOD) and dust deposition. Additional comparisons to Angström Exponent (AE), coarse mode AOD and dust surface concentration are included to extend the assessment of model performance. These datasets form a benchmark data set which is proposed for model inspection and future dust model developments. In general, models perform better in simulating climatology of vertically averaged integrated parameters (AOD and AE) in dusty sites than they do with total deposition and surface concentration. Almost all models over-estimate deposition fluxes over Europe, the Indian Ocean, the Atlantic Ocean and ice core data. Differenecs among the models arise when simulating deposition at remote sites with low fluxes over the Pacific and the Southern Atlantic Ocean. This study also highlights important differences in models ability to reproduce the deposition flux over Antarctica. The cause of this discrepancy could not be identified but different dust regimes at each site and issues with data quality should be considered. Models generally simulate better surface concentration at stations downwind of the main sources than at remote ones. Likewise, they simulate better surface concentration at stations affected by Saharan dust than at stations affected by Asian dust. Most models simulate the gradient in AOD and AE between the different dusty regions, however the seasonality and ...