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End date: 2009 × Start date: 2000 × Has files: Yes × Type: Text × Subject: numerical model × WGL Institute: TROPOS ×

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    Saharan dust transport and deposition towards the tropicalnorthern Atlantic
    (Göttingen : Copernicus, 2009) Schepanski, K.; Tegen, I.; MacKe, A.
    We present a study of Saharan dust export towards the tropical North Atlantic using the regional dust emission, transport and deposition model LM-MUSCAT. Horizontal and vertical distribution of dust optical thickness, concentration, and dry and wet deposition rates are used to describe seasonality of dust export and deposition towards the eastern Atlantic for three typical months in different seasons. Deposition rates strongly depend on the vertical dust distribution, which differs with seasons. Furthermore the contribution of dust originating from the Bod́eĺe Depression to Saharan dust over the Atlantic is investigated. A maximum contribution of Bod́eĺe dust transported towards the Cape Verde Islands is evident in winter when the Bod́eĺe source area is most active and dominant with regard to activation frequency and dust emission. Limitations of using satellite retrievals to estimate dust deposition are highlighted.
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    Columnar modelling of nucleation burst evolution in the convective boundary layer - First results from a feasibility study, Part I: Modelling approach
    (München : European Geopyhsical Union, 2006) Hellmuth, O.
    A high-order modelling approach to interpret "continental-type" particle formation bursts in the anthropogenically influenced convective boundary layer (CBL) is proposed. The model considers third-order closure for planetary boundary layer turbulence, sulphur and ammonia chemistry as well as aerosol dynamics. In Paper I of four papers, previous observations of ultrafine particle evolution are reviewed, model equations are derived, the model setup for a conceptual study on binary and ternary homogeneous nucleation is defined and shortcomings of process parameterisation are discussed. In the subsequent Papers II, III and IV simulation results, obtained within the framework of a conceptual study on the CBL evolution and new particle formation (NPF), will be presented and compared with observational findings.