Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 14, 13497-13514, 2014
http://www.atmos-chem-phys.net/14/13497/2014/
doi:10.5194/acp-14-13497-2014
© Author(s) 2014. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
19 Dec 2014
Aerosol radiative effects in the ultraviolet, visible, and near-infrared spectral ranges using long-term aerosol data series over the Iberian Peninsula
D. Mateos1,2, M. Antón1, C. Toledano2, V. E. Cachorro2, L. Alados-Arboledas3,4, M. Sorribas3,4,5, M. J. Costa6, and J. M. Baldasano7 1Departamento de Física, Universidad de Extremadura, Badajoz, Spain
2Grupo de Óptica Atmosférica, Universidad de Valladolid, Valladolid, Spain
3Departamento de Física Aplicada, Universidad de Granada, Granada, Spain
4Andalusian Institute for Earth System Research, Universidad de Granada, Granada, Spain
5Estación de Sondeos Atmosféricos El Arenosillo, INTA, Huelva, Spain
6Évora Geophysics Centre and Dep. Physics, University of Évora, Évora, Portugal
7Universidad Politécnica de Cataluña, Barcelona, Spain
Abstract. A better understanding of aerosol radiative properties is a crucial challenge for climate change studies. This study aims at providing a complete characterization of aerosol radiative effects in different spectral ranges within the shortwave (SW) solar spectrum. For this purpose, long-term data sets of aerosol properties from six AERONET stations located in the Iberian Peninsula (southwestern Europe) have been analyzed in terms of climatological characterization and inter-annual changes. Aerosol information was used as input for the libRadtran model in order to determine the aerosol radiative effect (ARE) at the surface in the ultraviolet (AREUV), visible (AREVIS), near-infrared (ARENIR), and the entire SW range (ARESW) under cloud-free conditions. Over the whole Iberian Peninsula, yearly aerosol radiative effects in the different spectral ranges were found to be −1.1 < AREUV < −0.7, −5.7 < AREVIS < −3.5, −2.6 < ARENIR < −1.6, and −8.8 < ARESW < −5.7 (in W m−2). Monthly means of ARE showed a seasonal pattern with larger values in spring and summer. The aerosol forcing efficiency (AFE), ARE per unit of aerosol optical depth, has also been evaluated in the four spectral ranges. AFE exhibited a dependence on single scattering albedo as well as a weaker one on the Ångström exponent. AFE is larger (in absolute value) for small and absorbing particles. The contributions of the UV, VIS, and NIR ranges to the SW efficiency varied with the aerosol types. The predominant aerosol size determined the fractions AFEVIS/AFESW and AFENIR/AFESW. The AFEVIS was the dominant contributor for all aerosol types, although non-absorbing large particles caused more even contribution of VIS and NIR intervals. The AFEUV / AFESW ratio showed a higher value in the case of absorbing fine particles.

Citation: Mateos, D., Antón, M., Toledano, C., Cachorro, V. E., Alados-Arboledas, L., Sorribas, M., Costa, M. J., and Baldasano, J. M.: Aerosol radiative effects in the ultraviolet, visible, and near-infrared spectral ranges using long-term aerosol data series over the Iberian Peninsula, Atmos. Chem. Phys., 14, 13497-13514, doi:10.5194/acp-14-13497-2014, 2014.
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Short summary
A long-term analysis of aerosol radiative effects over the Iberian Peninsula is carried out. A reduction of aerosol effects on solar radiation at the surface is observed in the 2000s. Aerosol forcing efficiency is stronger for small and absorbing particles. The contributions of the ultraviolet, visible, and near-infrared spectral intervals to the total shortwave efficiency vary with the aerosol types, producing the visible range the dominant contribution for all aerosol types.
A long-term analysis of aerosol radiative effects over the Iberian Peninsula is carried out. A...
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