AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Saharan Dust in Southern Europe in the Period 2001-2011: Estimation and Geographical Distribution
J. PEY, N. Pérez, Xavier Querol, Andrés Alastuey, F. Forastiere, M. Stafoggia, Aix-Marseille Université-CNRS, LCE FRE 3416
Abstract Number: 324 Working Group: Remote and Regional Atmospheric Aerosols
Abstract African dust outbreaks affecting southern Europe were studied on an 11-year period (2001-2011), in the context of the MED-PARTICLES (LIFE programme, EU) project. The daily influence of African dust was identified in 17 geographical areas. A methodology for the quantification of daily African dust inputs to PM10 concentrations was applied.
African dust outbreaks are more frequent in the most southern European regions, from 30 to 37 % of the annual days, whereas they occur less than 20% of the annual days in northern sites of the Mediterranean basin. A decreasing south to north gradient of African dust contribution to PM10, driven by the latitudinal position of the monitoring sites is patent across the Mediterranean. From 25ºE eastwards, higher annual dust contributions are encountered due to the elevated annual occurrence of severe episodesof dust but also because of inputs from Middle Eastern deserts. Overall, African dust emerges as the largest PM10 source in regional background southern sites of the Mediterranean (35-50% of PM10), with seasonal peak contributions to PM10 up to 80% of the total mass in the eastern side.
The multi-year study of African dust episodes and their contributions to PM10 concentrations displays a consistent decreasing trend in the period 2006/2007 to 2011 in 4 of the 17 studied regions, all of them located in the NW of the Mediterranean. Such decrease is almost parallel to that of NAO (North Atlantic Oscillation) index for the summer period, being progressively more negative since 2006. As a consequence, a sharp change in the atmospheric circulation over the last 5 years (a similar negative NAO period occurred in the 1950 decade) have affected the number of African dust episodes and consequently the annual dust inputs to PM10 observed in the NW part of the Mediterranean.