ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-12-2933-2012 Atmospheric dust modeling from meso to global scales with the online NMMB/BSC-Dust model – Part 2: Experimental campaigns in Northern Africa Haustein K. 1 2 15 Pérez C. 3 4 5 Baldasano J. M. 1 6 Jorba O. 1 Basart S. 1 Miller R. L. 3 4 Janjic Z. 7 Black T. 7 Nickovic S. 8 Todd M. C. 9 Washington R. 2 Müller D. 10 14 16 Tesche M. 11 Weinzierl B. 12 Esselborn M. 12 13 Schladitz A. 14 Barcelona Supercomputing Center, Earth Science Department, Barcelona, Spain Climate Research Group, Centre for the Environment, University of Oxford, Oxford, UK NASA Goddard Institute for Space Studies, New York, USA Department of Applied Physics and Applied Math, Columbia University, New York, USA International Research Institute for Climate and Society, Palisades, New York, USA Environmental Modeling Laboratory, Technical University of Catalonia, Barcelona, Spain Environmental Modeling Center, National Centers for Environmental Prediction, Camp Springs, Maryland, USA Research Department, World Meteorological Organization, Geneva, Switzerland Department of Geography, University of Sussex, Brighton, UK School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, South Korea Department of Environmental Science, Stockholm University, Stockholm, Sweden Deutsches Zentrum fur Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany European Southern Observatory, Technology Division, Garching, Germany Leibniz Institute for Tropospheric Research, Leipzig, Germany now at: Climate Research Group, Centre for the Environment, University of Oxford, Oxford, UK now at: Science Systems and Applications Inc., NASA Langley Research Center, Hampton, Virginia, USA 23 03 2012 12 6 2933 2958 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/12/2933/2012/acp-12-2933-2012.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/12/2933/2012/acp-12-2933-2012.pdf

The new NMMB/BSC-Dust model is intended to provide short to medium-range weather and dust forecasts from regional to global scales. It is an online model in which the dust aerosol dynamics and physics are solved at each model time step. The companion paper (Pérez et al., 2011) develops the dust model parameterizations and provides daily to annual evaluations of the model for its global and regional configurations. Modeled aerosol optical depth (AOD) was evaluated against AERONET Sun photometers over Northern Africa, Middle East and Europe with correlations around 0.6–0.7 on average without dust data assimilation. In this paper we analyze in detail the behavior of the model using data from the Saharan Mineral dUst experiment (SAMUM-1) in 2006 and the Bodélé Dust Experiment (BoDEx) in 2005. AOD from satellites and Sun photometers, vertically resolved extinction coefficients from lidars and particle size distributions at the ground and in the troposphere are used, complemented by wind profile data and surface meteorological measurements. All simulations were performed at the regional scale for the Northern African domain at the expected operational horizontal resolution of 25 km. Model results for SAMUM-1 generally show good agreement with satellite data over the most active Saharan dust sources. The model reproduces the AOD from Sun photometers close to sources and after long-range transport, and the dust size spectra at different height levels. At this resolution, the model is not able to reproduce a large haboob that occurred during the campaign. Some deficiencies are found concerning the vertical dust distribution related to the representation of the mixing height in the atmospheric part of the model. For the BoDEx episode, we found the diurnal temperature cycle to be strongly dependant on the soil moisture, which is underestimated in the NCEP analysis used for model initialization. The low level jet (LLJ) and the dust AOD over the Bodélé are well reproduced. The remaining negative AOD bias (due to underestimated surface wind speeds) can be substantially reduced by decreasing the threshold friction velocity in the model.

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