1Environmental Department of the Research Center for Energy, Environment and Technology (CIEMAT) – Unidad Asociada en Contaminación Atmosférica CSIC-CIEMAT, Avenida Complutense 40, 28040 Madrid, Spain
2Institute of Environmental Assessment & Water Research (IDǼA-CSIC). c/Jordi Girona 18, 08034 Barcelona, Spain
3Centro de Investigación Atmosférica de Izaña, Agencia Estatal de Meteorología (AEMET) c/La Marina 20, Santa Cruz de Tenerife, 38071, Spain
4Universidad Europea de Canarias, Laureate International Universities, C/Inocencio García, 1, 38300 La Orotava, Spain
5Aix-Marseille Université, CNRS, LCE FRE 3416, Marseille, 13331, France
Received: 13 Jan 2014 – Published in Atmos. Chem. Phys. Discuss.: 03 Mar 2014
Abstract. The occurrence of African dust outbreaks over different areas of the western Mediterranean Basin were identified on an 11-year period (2001–2011). The main atmospheric circulation patterns causing the transport of African air masses were characterized by means of an objective classification methodology of atmospheric variable fields. Next, the potential source areas of mineral dust, associated to each circulation pattern were identified by trajectory statistical methods. Finally, an impact index was calculated to estimate the incidence of the African dust outbreaks produced during each circulation pattern, in the areas of study.
Revised: 27 May 2014 – Accepted: 29 May 2014 – Published: 03 Jul 2014
Four circulation types were obtained (I–IV) and three main potential source areas of African dust were identified (Western Sahara and Morocco; Algeria; northeastern Algeria and Tunisia). The circulation pattern I (24% of the total number of episodic days) produced the transport of dust mainly in summer from Western Sahara, southern Morocco and Tunisia. The circulation pattern IV (33%) brings dust mainly from areas of northern and southern Algeria in summer and autumn, respectively. The circulation pattern II (31%) favored the transport of dust predominantly from northern Algeria, both in spring and summer. Finally, the circulation type III was the less frequently observed (12%). It occurred mainly in spring and with less intensity in winter, carrying dust from Western Sahara and southern Morocco.
Our findings point out that the most intense episodes over the western Mediterranean Basin were produced in the summer period by the circulation type I (over the western side of the Iberian Peninsula) and the circulation type IV (over the central and eastern sides of the Iberian Peninsula and the Balearic Islands).
Salvador, P., Alonso-Pérez, S., Pey, J., Artíñano, B., de Bustos, J. J., Alastuey, A., and Querol, X.: African dust outbreaks over the western Mediterranean Basin: 11-year characterization of atmospheric circulation patterns and dust source areas, Atmos. Chem. Phys., 14, 6759-6775, doi:10.5194/acp-14-6759-2014, 2014.