Volume 12, No. 5, October 2012, Pages 856-878 PDF(1.36 MB)
Air Masses and Weather Types: A Useful Tool for Characterizing Precipitation Chemistry and Wet Deposition
A.I. Calvo1, V. Pont2, F.J. Olmo3,4, A. Castro5, L. Alados-Arboledas3,4, A.M. Vicente1, M. Fernández-Raga5, R. Fraile5
1 Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Aveiro 3810-193, Portugal
2 Laboratoire d’Aérologie /OMP, UMR 5560, Université de Toulouse III, CNRS-UPS, 14, av. E. Belin, Toulouse 31400, France
3 Atmospheric Physics Group, CEAMA, University of Granada. Junta de Andalucía, Granada 18006, Spain
4 Department of Applied Physics. University of Granada, Granada 18071, Spain
5 Department of Physics, IMARENAB, University of León, León 24071, Spain
This study is an analysis of 344 days with rainfall recorded during five years in a remote regional background EMEP (Cooperative Programme for the Monitoring and Evaluation of the Long Range Transmission of Air Pollutants in Europe) station in Spain. The chemical composition of the rainwater associated with air masses (nine categories) and weather types (26 categories) was characterized. The chemical composition of rainwater was dominated by calcium (Ca2+) and sulphate (SO42−-S), with VWM (Volume Weighted Mean) during the period studied (2002–2006), with 55 μeq/L and 34 μeqS/L, respectively. Calcium, sodium (Na+), ammonium (NH4+-N) and magnesium (Mg2+) seem to be dominant components in the neutralization of the rainwater. By applying Pearson correlations, principal component analysis and enrichment factors, it is possible to identify source types for the precipitation constituents. Interannual and intra-annual variability was also been studied. High calcium levels are associated with the frequent intrusions of Saharan dust that occur during the summer, and the maximums of chlorine and sodium in the winter may be due to the greater amount of maritime air recorded during this season. Wet deposition was determined by focusing on nitrogen deposition, registering mean annual values of 155 mgN/m2/year (from the NO3−-N) and 165 mgN/m2/year (from the NH4+-N).
Rainwater chemical composition; Trajectory analysis; Circulation weather types; N deposition; Wet deposition.