Long-term aerosol measurements in Gran Canaria, Canary Islands: Particle concentration, sources and elemental composition

• Published in: Journal of Geophysical Research: Atmospheres Vol. 117; no. D3
• Main Authors: Gelado-Caballero, María D., López-García, Patricia, Prieto, Sandra, Patey, Matthew D., Collado, Cayetano, Hérnández-Brito, José J.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 16-02-2012; American Geophysical Union
• Subjects: aerosol; Aerosols; Air masses; Annual variations; Biological oceanography; Canary region; Chemical composition; Chemical oceanography; Deserts; Dry deposition; Dust; Earth sciences; Earth, ocean, space; elemental composition; Exact sciences and technology; Geophysics; metals; particle concentration; Sea level; Iberian Peninsula; Canary Islands; Europe; Atlantic Ocean; Africa; Southern Europe; North Atlantic; Atlantic Ocean Islands; Sahel; Spain; Sahara; AN, North Atlantic; Africa, Sahara Desert; ASE, Atlantic, Canary Is., Gran Canaria; ASE, Atlantic, Canary Is; ANE, Atlantic, Azores, Pico; AN, North Atlantic, North Atlantic Oscillation; ANE, Spain; aerosols; NOAA; Summer; concentration; aluminum; pollution; Long term; Dry deposition; Atmospheric dust; homogeneity; Interannual variation; North Atlantic oscillation; Suspended particle; deserts; Enrichment factor; Air mass; bedrock; Winter; islands; sea level
• ISSN: 0148-0227; 2169-897X; 2156-2202; 2169-8996
• DOI: 10.1029/2011JD016646

There are very few sets of long‐term measurements of aerosol concentrations over the North Atlantic Ocean, yet such data is invaluable in quantifying atmospheric dust inputs to this ocean region. We present an 8‐year record of total suspended particles (TSP) collected at three stations on Gran Canaria Island, Spain (Taliarte at sea level, Tafira 269 m above sea level (a.s.l.) and Pico de la Gorra 1930 m a.s.l.). Using wet and dry deposition measurements, the mean dust flux was calculated at 42.3 mg m−2 d−1. Air mass back trajectories (HYSPLIT, NOAA) suggested that the Sahara desert is the major source of African dust (dominant during 32–50% of days), while the Sahel desert was the major source only 2–10% of the time (maximum in summer). Elemental composition ratios of African samples indicate that, despite the homogeneity of the dust in collected samples, some signatures of the bedrocks can still be detected. Differences were found for the Sahel, Central Sahara and North of Sahara regions in Ti/Al, Mg/Al and Ca/Al ratios, respectively. Elements often associated with pollution (Pb, Cd, Ni, Zn) appeared to share a common origin, while Cu may have a predominantly local source, as suggested by a decrease in the enrichment factor (EF) of Cu during dust events. The inter‐annual variability of dust concentrations is investigated in this work. During winter, African dust concentration measurements at the Pico de la Gorra station were found to correlate with the North Atlantic Oscillation (NAO) index.
Key Points
Chemical characterization of African aerosol samples collected in Gran Canaria
Identification of African aerosol origin using metal ratios
Air‐mass back trajectory classification in Gran Canaria during 2004‐2009