Mineral dust particles affect the atmospheric radiation budget through absorption and scattering of incoming solar radiation, and absorption and reemission of outgoing long-wave radiation. The Intergovernmental Panel on Climate Change (IPCC)  has identified mineral dust as the aerosol with major uncertainty in the climate system. Both the magnitude and the sign of the dust direct radiative forcing remain unresolved and depend on the optical properties of dust, its vertical distribution, cloud cover, and albedo of the underlying surface. The major direct forcing uncertainties are related to the degree of absorbed solar radiation [Sokolik and Toon, 1999], the influence on long-wave radiation and the global amount of dust in the atmosphere.
 Other uncertainties relate to the effect of dust on cloud formation and precipitation. Concerning the indirect effect (microphysical cloud-dust interactions), Rosenfeld et al.  observed that mineral dust generates large concentrations of cloud condensation nuclei (CCN), mostly in the small size range that can lead to cloud formation dominated by small droplets. As a result, this could lead to droplet coalescence reduction and suppressed precipitation. Levin et al.  on the other hand found out that mineral dust coated with sulfate and other soluble materials can generate large CCN and consequently large drops, which would accelerate precipitation development through a droplet growth by collection. Additionally, by the so-called “semidirect” effect dust affecting the thermal atmospheric structure can modify cloud formation [Hansen et al., 1997].
 Many studies have explored the radiative forcing of mineral dust [e.g., Tegen and Lacis, 1996; Sokolik and Toon, 1996; Quijano et al., 2000; Woodward, 2001; Myhre et al., 2003] with a wide range of results. Miller and Tegen  examined the radiative effect in a climate model by using prescribed dust distributions. In spite of simplified dust representation in this study, dust and atmosphere generated complex interactions: the increased dust load modified the thermal and dynamic structure of the air and the modified atmosphere furthermore changed dust emission, transport and deposition. More recently, Perlwitz et al.  and Miller et al. [2004a, 2004b] interactively coupled a dust aerosol model and a general circulation model (GCM).
 Several other studies suggest that the inclusion of mineral dust radiative effects would improve the radiation balance of numerical weather prediction (NWP) models and thus increase overall accuracy of the weather prediction itself [Kischa et al., 2003; Haywood et al., 2005].
 Most of current weather forecasting models use prespecified (climatological or other) ozone and CO2 profiles in radiation calculations. Concerning the mineral aerosol and its impact on radiation, current situation is rather unsatisfactory. To our knowledge, none of the operational atmospheric models uses online predicted mineral aerosol concentration for radiation calculations. For example, the NCEP regional models (Eta and NMM) use the solar constant reduced by 3% anywhere anytime to represent aerosol influence. Advances in dust modeling over the last decade have achieved today a level permitting rather accurate dust concentration inputs for calculating dust-radiation interactions. For example, the DREAM dust operational model [Nickovic et al., 2001] is capable of predicting major dust events with considerable accuracy [Yin et al., 2005; Pérez et al., 2006].
 Following the idea of improving weather forecasts by including the dust radiative effect, we have completed and refined some preliminary studies [Nickovic et al., 2004; Nickovic, 2005]. A parameterization scheme that considers dust aerosol as a radiatively active substance interacting with short- and long-wave radiation has been developed. The modeling system uses the limited-area NCEP/Eta model as an atmospheric driver of the DREAM model. The developed parameterization scheme that integrates these two model components permits two-way interactions between dust and the atmosphere. Within every model time step both dust and atmospheric fields are updated through their mutual influences.
 The paper is structured as follows: in section 2 we describe the DREAM modeling system and the new developments introduced. Two simulations of a major dust outbreak that occurred in the Mediterranean region on April 2002 are performed. In the first experiment dust is considered as a dynamic tracer without any radiative interaction. In the other experiment, interaction between short- and long-wave radiation and dust is included. In section 3 we explore the dust direct radiative effects on solar and terrestrial wavelengths, the changes produced on surface turbulent fluxes and the feedback upon dust emission. In this section we also evaluate the forecasted atmospheric temperature and mean sea level pressure from both experiments against objective analysis.