Modulation of Saharan dust export by the North African dipole

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dc.contributor.author Rodríguez, S.
dc.contributor.author Cuevas, Emilio
dc.contributor.author Prospero, J. M.
dc.contributor.author Alastuey, A.
dc.contributor.author Querol, X.
dc.contributor.author López-Solano, J.
dc.contributor.author García, M. I.
dc.contributor.author Alonso Pérez, Silvia
dc.date.accessioned 2017-05-12T10:40:34Z
dc.date.available 2017-05-12T10:40:34Z
dc.date.issued 2015
dc.identifier.citation Rodríguez, S., Cuevas, E., Prospero, J. M., Alastuey, A., Querol, X., López-Solano, J., ... & Alonso-Pérez, S. (2015). Modulation of Saharan dust export by the North African dipole. Atmospheric Chemistry and Physics, 15(13), 7471-7486. DOI: 10.5194/acp-15-7471-2015 spa
dc.identifier.issn 16807316
dc.identifier.issn 16807324
dc.identifier.uri http://hdl.handle.net/11268/6387
dc.description.abstract We have studied the relationship between the long-term interannual variability in large-scale meteorology in western North Africa – the largest and most active dust source worldwide – and Saharan dust export in summer, when enhanced dust mobilization in the hyper-arid Sahara results in maximum dust impacts throughout the North Atlantic. We address this issue by analyzing 28 years (1987–2014) of summer averaged dust concentrations at the high-altitude Izaña observatory (~ 2400 m a.s.l.) on Tenerife, and satellite and meteorological reanalysis data. The summer meteorological scenario in North Africa (aloft 850 hPa) is characterized by a high over the the subtropical Sahara and a low over the tropics linked to the monsoon. We measured the variability of this high–low dipole-like pattern in terms of the North African dipole intensity (NAFDI): the difference of geopotential height anomalies averaged over the subtropics (30–32° N, Morocco) and the tropics (10–13° N, Bamako region) close to the Atlantic coast (at 5–8° W). We focused on the 700 hPa standard level due to dust export off the coast of North Africa tending to occur between 1 and 5 km a.s.l. Variability in the NAFDI is associated with displacements of the North African anticyclone over the Sahara and this has implications for wind and dust export. The correlations we found between the 1987–2014 summer mean of NAFDI with dust at Izaña, satellite dust observations and meteorological re-analysis data indicate that increases in the NAFDI (i) result in higher wind speeds at the north of the Inter-Tropical Convergence Zone that are associated with enhanced dust export over the subtropical North Atlantic, (ii) influence the long-term variability of the size distribution of exported dust particles (increasing the load of coarse dust) and (iii) are associated with enhanced rains in the tropical and northern shifts of the tropical rain band that may affect the southern Sahel. Interannual variability in NAFDI is also connected to spatial distribution of dust over the North Atlantic; high NAFDI summers are associated with major dust export (linked to winds) in the subtropics and minor dust loads in the tropics (linked to higher rainfall), and vice versa. The evolution of the summer NAFDI values since 1950 to the present day shows connections to climatic variability (through the Sahelian drought, ENSO (El Niño–Southern Oscillation) and winds) that have implications for dust export paths. Efforts to anticipate how dust export may evolve in future decades will require a better understanding of how the large-scale meteorological systems represented by the NAFD will evolve. spa
dc.description.sponsorship The Izaña GAW program is funded by AEMET and by the Minister of Economy and Competitiveness of Spain (POLLINDUST, CGL2011-26259) spa
dc.description.sponsorship J. M. Prospero’s research is supported by NSF grant AGS-0962256 spa
dc.language.iso eng spa
dc.rights Reconocimiento 3.0 *
dc.rights.uri https://creativecommons.org/licenses/by/3.0/es/ *
dc.title Modulation of Saharan dust export by the North African dipole spa
dc.type article spa
dc.description.impact 5.114 JCR (2015) Q1, 6/84 Meteorology and atmospheric sciences spa
dc.identifier.doi 10.5194/acp-15-7471-2015
dc.rights.accessRights openAccess spa
dc.subject.uem Meteorología - Sahara spa
dc.subject.unesco Meteorología spa
dc.subject.unesco Sahara spa
dc.description.filiation UEC spa
dc.peerreviewed Si spa

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