Operational Regional Dust Forecast and Satellite Monitoring With the NCEP/ETA Model in the North African and Mediterranean Area

The NCEP/ETA numerical weather prediction model is a comprehensive and mature model used successfully world-wide for synoptic scale regional forecasting up to three days ahead. The desert cycle is implemented in the NCEP/ETA model by means of the following major components: 1. Dust uptake, using surface characteristics and low level atmospheric turbulence; 2. Dust transport and distribution (horizontal and vertical advection and diffusion); 3. Dust removal (dry and wet deposition). The model was used quasi-operationally for daily dust forecast and dust alert service in the Mediterranean area between March 1997 and March 1998, in the frame of the EU-funded Mediterranean Dust Experiment (MEDUSE). Dust simulations were enhanced by operational daily monitoring of the dust load over Africa and seawater, based on Meteosat satellite data. Not a single dust event of significance was missed out by the model forecasts, and dust alerts allowed a number of complementary dust ground-based and airborne observations. MEDUSE simulations and more recent cases with different synoptic characteristics, tested against satellite images, visibility measurements and in situ observations as available, will be presented. Special emphasis will be given on the effect of the horizontal resolution on the model results through a detailed case study.