Desert dust characterization in Northern Africa, Middle East and Europe through regional dust modelling, and satellite-borne and ground-based observations

The impact of mineral dust upon climate, ecosystems and air quality represents a major scientific and societal issue. The aim goals of the present Ph.D. Thesis are to evaluate the behaviour and to improve the forecasting skills of a regional dust model and to characterize the desert dust content in Northern Africa, Europe and Middle East. An aerosol characterization was performed using long-term series of aerosol optical depth (AOD) from AERONET sun photometers. The results showed that mineral dust was the most important constituent in Northern Africa and Arabia. Small particles were abundant in sites close to urban and industrial areas of Continental and Eastern Europe and Middle East, and important contributions of biomass burning were observed in the sub-Sahel region in winter. Desert dust transport to Southern Europe was observed from spring to autumn and decreasing with latitude with contributions above 40% to the aerosol column load. Dust models are essential to complement dust-related observations, understand the dust processes and predict the impact of dust on air quality. Despite that the BSC-DREAM8b model has reached a level of delivering reliable operational dust forecasts, it is necessary to conduct an extensive evaluation of its behaviour. The BSC-DREAM8b and the original DREAM models and different research model versions were evaluated over Northern Africa, Mediterranean and Middle East using AERONET measurements and seasonal averages from satellite aerosol products. The model evaluation highlighted that BSC-DREAM8b and DREAM strongly underestimated the dust fields in the Sahel during winter and overestimated dust concentrations during spring rainy events in the Mediterranean. The introduction of new dry deposition scheme and an updates in the wet deposition scheme improved the long-range transport, although significant underestimation remained in the Sahel in winter. The inclusion of a preferential source mask improved the localization of the main North African sources and the long-range dust transport to Europe and Atlantic regions. The inclusion of a more physically-based dust emission scheme with a new soil texture database led to reasonably good results at source areas and subsequent long-range transport. In this case, the use of a preferential source mask didn¿t introduce significant improvements. The long-range dust transport over Europe was evaluated and analysed with an annual simulation of the CALIOPE air quality modelling system. C