PI	Stavros Solomos, Slobodan Nickovic
Participants	National Observatory of Athens
	University of Belgrade

Dust forecasts are provided by DREAM-NMM model. The meteorological core is the NCEP Nonhydrostatic Mesoscale Model on E-grid (NCEP/NMME) (Janjic et al., 2001). Surface properties are defined using the USGS global 1-km land cover data and the USDA global 1-km soil. The model is configured at 0.2°×0.2° resolution and includes 8 dust size bins with effective radii of 0.15, 0.25 0.45, 0.78, 1.3, 2.2, 3.8 and 7.1 μm respectively. The model is running in three different configurations:

1. DREAM-NMM (Nickovic et al., 2001) without assimilation and GFS initial and boundary conditions, operated by NOA.

2. DREAM-NMM-ECMWF-assim (Nickovic et al., 2001; Pejanovic et al., 2010) with assimilation of the ECMWF dust aerosol (Benedetti et al., 2009) and ECMWF initial and boundary conditions, operated by IPB. This model version includes the parameterization of dust-induced ice nuclei concentration (#IN) (Nickovic et al., 2016) to predict conditions for cold cloud formation. For temperatures in the interval (-36°C; -5°C), we use the immersion ice nucleation parameterization developed by DeMott et al. (2015). For temperatures in the interval (-55°C; -36°C), we use the Steinke et al. (2015) parameterization for the deposition ice nucleation. In addition to conventional model products (e.g. AOD, dust concentration), the extinction coefficient is also added to the output parameter list of the model.

3. DREAM-NMM-MSG-assim (Pejanovic et al., 2010; Solomos et al., 2016) with assimilation of the UK Met Office MSG-SEVIRI dust product (Brindley and Russell, 2009) and GFS initial and boundary conditions, operated by NOA.

Complimentary simulations with alternative model configurations are also active during PRE-TECT for the purpose of model sensitivity studies.

References

Brindley, H. E., and J. E. Russell (2009), An assessment of Saharan dust loading and the corresponding cloud-free longwave direct radiative effect from geostationary satellite observations, J. Geophys. Res., Vol 114, 148-227.