Synoptic patterns associated with extreme dust events in the Mediterranean Basin

Abstract

Extreme dust events over the western, central and eastern Mediterranean are identified analysing the aerosol optical depth remote-sensed by the Moderate Resolution Imaging Spectroradiometer (MODIS) in 2001-2010 and simulated by the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model in 2000-2007. The seasonal variability of the dust events and the evolution of the synoptic circulation patterns before and during the events are studied. Results show that the highest occurrence of short events (1-3 days) is in the eastern Mediterranean, while long events (more than 4 days) are more frequent in the western Mediterranean. Short events are concentrated in spring, while long events do not show a clear seasonality. The synoptic circulation patterns accompanying short and long events are similar, and the occurrence across the Mediterranean Basin is related to westerly low-pressure systems. Dust events in the western Mediterranean are associated with high-pressure conditions limiting the development of lows to the western North Africa, while the eastward evolution of cyclones over the central Mediterranean and Northern Africa accompanies dust events in the central and eastern Mediterranean.

Phytoplankton Response to Saharan Dust Depositions in the Eastern Mediterranean Sea: A Mesocosm Study

“…The positive response of phytoplankton to dust addition is largely in accordance with many previous microcosm and mesocosm experiments performed in oligotrophic low nutrients low chlorophyll (LNLC) sites, such as in the east ( ; Tsagaraki et al, in review) and west Mediterranean basins (Bonnet et al, 2005;Lekunberri et al, 2010;Romero et al, 2011;Ridame et al, 2014), in the Atlantic Ocean (Marañón et al, 2010) and in South China Sea (Guo et al, 2012). Besides the single-addition experiment, additional mesocosm containers were subjected to three consecutive inoculations with smaller amounts of Saharan dust (RA treatment) in order to better simulate the recurrent pattern of Saharan dust events in the eastern Mediterranean, where continuing dust deposition events may occur over a period of several days (Meloni et al, 2008;Gaetani and Pasqui, 2014;Vincent et al, 2016). The sum of the three dust additions equaled the amount of dust added in the SA treatment.…”

The climate of the Mediterranean region: research progress and climate change impacts

“…Both explosive and ordinary cyclones have become less frequent in the analyzed period in the Mediterranean basin. Gaetani and Pasqui (2014) identify extreme dust events in the Mediterranean Basin during the period 2001-2010 using aerosol remote-sensed optical depth and model simulations. Dust events in the western Mediterranean are associated with high-pressure conditions, limiting the development of lows to the western North Africa, while the eastward evolution of cyclones over the central Mediterranean and Northern Africa accompanies dust events in the central and eastern Mediterranean.…”

Atmospheric circulation evolution related to desert‐dust episodes over the Mediterranean

“…Finally, the prevailing atmospheric circulation patterns favouring the transport of mineral particles from Sahara to the Mediterranean basin were studied by Varga et al (2014), who used the aerosol index as an indicator of dust particles and cluster analysis to classify the geopotential height fields at 700 hPa. The relationship between the prevailing synoptic conditions and the occurrence of dust events in the Mediterranean also has been the subject of other research, such as that by Gaetani and Pasqui (2012) based on satellite (MODIS) and model Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) data and that by Calastrini et al (2012) based on ground measurements of PM and application of various models.…”