Seven years of measurements of aerosol scattering properties, near the surface, in the southwestern Iberia Peninsula

Pereira, S.; Wagner, Frank; Silva, Ana Maria

doi:10.5194/acp-11-17-2011

Cited by 66 publications

(65 citation statements)

References 29 publications

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“…For a calculated mean a of 1.3 the daily PM 1 /PM 10 and PM 2.5 /PM 10 ratios were found around 0.6 and 0.8 respectively indicating a higher percentage of small particles in the atmosphere compared with coarse particles. As reported in Pereira et al (2011) about 60-70 % of the light is scattered by submicron particles for anÅngström exponent of 1.5. As shown in the following of this work, the submicron particles dominated even more the light scattering at MSY under specific atmospheric conditions leading to the presence of polluted air masses at MSY station.…”

Section: General Featuresmentioning

confidence: 78%

“…As shown in this work, the in-situ measurements are helpful in order to describe the effects of mesoscale weather systems such as the breeze circulation on aerosol optical properties. A number of studies have been published on in-situ aerosol optical measurements in the Eastern Mediterranean (Vrekoussis et al, 2005;Ichoku et al, 1999;Formenti et al, 2001;Sciare et al, 2005;Kouvarakis et al, 2002;Andreae et al, 2002;Gerasopoulos et al, 2003;Sabbah et al, 2001;Israelevich et al, 2002), Central Mediterranean and South Italy (Pace et al, 2006;Esposito et al, 2004), South Iberian Peninsula (Pereira et al, 2011;Lyamani et al, 2008). However, little has been published on aerosol optical properties in the Western Mediterranean Basin (Mallet et al, 2003;Saha et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…The skewness measures the asymmetry of a distribution function and the higher the skewness, the higher the probability of measuring levels higher than the mean for the considered aerosol component or parameter. All variables reported in Table 1 Matthias and Bösenberg, 2002;Pereira et al, 2011). Thus, as shown in Sect.…”

Section: Data Processingmentioning

confidence: 99%

“…In Artic remote sites mean scattering and absorption coefficients lower than 10 Mm −1 and 1 Mm −1 , respectively were measured (Aaltonen et al, 2006;Delene and Ogren, 2002 (Lyamani et al, 2006). Recently, mean scattering and backscattering coefficients of 42.5 Mm −1 and 5.9 Mm −1 respectively were measured in a small city quite far from pollution sources in the southwestern Portugal (Pereira et al, 2011). The MSY measurement site can be considered as a regional background site influenced -under specific atmospheric conditions as discussed in the following paragraphsby emissions from the urbanized/industrialized WMB coastline.…”

Section: General Featuresmentioning

confidence: 99%

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Variability of aerosol optical properties in the Western Mediterranean Basin

et al. 2011

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Abstract. Aerosol light scattering, absorption and particulate matter (PM) concentrations were measured at Montseny, a regional background site in the Western Mediterranean Basin (WMB) which is part of the European Supersite for Atmospheric Aerosol Research (EUSAAR). Off line analyses of 24 h PM filters collected with Hi-Vol instruments were performed for the determination of the main chemical components of PM. Mean scattering and hemispheric backscattering coefficients (@ 635 nm) were 26.6±23.2 Mm −1 and 4.3±2.7 Mm −1 , respectively and the mean aerosol absorption coefficient (@ 637 nm) was 2.8±2.2 Mm −1 . Mean values of Single Scattering Albedo (SSA) andÅngström exponent (å) (calculated from 450 nm to 635 nm) at MSY were 0.90±0.05 and 1.3±0.5 respectively. A clear relationship was observed between the PM 1 /PM 10 and PM 2.5 /PM 10 ratios as a function of the calculatedÅngström exponents. Mass scattering cross sections (MSC) for fine mass and sulfate at 635 nm were 2.8±0.5 m 2 g −1 and 11.8±2.2 m 2 g −1 , respectively, while the mean aerosol absorption cross section (MAC) was 10.4±2.0 m 2 g −1 . The variability in aerosol optical properties in the WMB were largely explained by the origin and ageing of air masses over the measurement site. The MAC values appear dependent of particles aging: similar to the expected absorption cross-section for fresh emissions under Atlantic Advection episodes and higher under aerosol pollution episodes. The analysis of theÅngström exponent as a function of the origin the air masses revealed that polluted winter anticyclonic conditions and summer recirculation scenarios typical of the WMB led to an increase of fine particles in the atmosphere (å = 1.5±0.1) while the aerosol optical properties under Atlantic Advection episodes and Saharan dust outbreaks were clearly dominated by coarser particles (å = 1.0±0.4). The sea breeze played an important role Correspondence to: M. Pandolfi (marco.pandolfi@idaea.csic.es) in transporting pollutants from the developed WMB coastlines towards inland rural areas, changing the optical properties of aerosols. Aerosol scattering and backscattering coefficients increased by around 40 % in the afternoon when the sea breeze was fully developed while the absorption coefficient increased by more than 100 % as a consequence of the increase in the equivalent black carbon concentration (EBC) observed at MSY under sea breeze circulation.

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Section: General Featuresmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Section: Data Processingmentioning

confidence: 99%

Section: General Featuresmentioning

confidence: 99%

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Variability of aerosol optical properties in the Western Mediterranean Basin

et al. 2011

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“…In addition to the desert dust intrusions, the Iberian Peninsula is notably affected by other sources of aerosols. In particular, the southwestern interior part of the Iberian Peninsula is also exposed to local continental aerosols and marine aerosols coming from the Atlantic Ocean (Pereira et al, 2005;Elias et al, 2006;Silva et al, 2006;Pereira et al, 2008;Pereira et al, 2011;Obregón et al, 2012). Additionally, wildfires are an occasional but intense source of aerosols for the area in summer.…”

Section: Introductionmentioning

confidence: 99%

Thirteen Years of Aerosol Radiative Forcing in Southwestern Iberian Peninsula

Muñoz

Costa

Silva

et al. 2017

Aerosol Air Qual. Res.

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Notable uncertainties in the aerosol impact on the Earth's radiative budget still remain, mainly at local scales. This study aims to accurately quantify the shortwave aerosol radiative forcing (ARF) and its efficiency (ARFE) at Évora (Portugal, Southwestern Europe). This is an interesting region affected by different aerosol types and sources. Towards this goal, ARF and ARFE are calculated for Évora during thirteen years (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015), which is the longest period ever analyzed for this region. For this calculation, the most updated AERONET data have been used to simulate irradiance with the libRadtran code. Thus, 1676 daily values were analyzed, obtaining a mean ARF of -7.4 W m -2 at the Earth's surface (SURF) and -1.1 W m -2 at the top of the atmosphere (TOA), indicating a cooling of the Earth-atmosphere system. The difference in ARF between TOA and SURF indicates a mean net gain of 6.3 W m -2 for the atmosphere. While no ARF seasonal pattern is observed at the TOA, a clear seasonal cycle is detected at the SURF with the most negative values occurring in summer. On the other hand, ARFE shows mean values of -62.7 W m -2 τ -1 at the SURF and -14.3 W m -2 τ -1 at the TOA. Results show that ARFE highly depends on the aerosol single scattering albedo, showing opposite behavior at the SURF and at the TOA. The large temporal variability detected in the aerosol properties in the region of study confirms the general need for long time series of measurements to achieve an accurate estimation of the ARF and ARFE.

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Investigation of the sources and evolution processes of severe haze pollution in Beijing in January 2013

et al. 2014

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China experienced severe haze pollution in January 2013. Here we have a detailed characterization of the sources and evolution mechanisms of this haze pollution with a focus on four haze episodes that occurred during 10-14 January in Beijing. The main source of data analyzed is from submicron aerosol measurements by an Aerodyne Aerosol Chemical Speciation Monitor. The average PM1 mass concentration during the four haze episodes ranged from 144 to 300 μg m À3, which was more than 10 times higher than that observed during clean periods. All submicron aerosol species showed substantial increases during haze episodes with sulfate being the largest. Secondary inorganic species played enhanced roles in the haze formation as suggested by their elevated contributions during haze episodes. Positive matrix factorization analysis resolved six organic aerosol (OA) factors including three primary OA (POA) factors from traffic, cooking, and coal combustion emissions, respectively, and three secondary OA (SOA) factors. Overall, SOA contributed 41-59% of OA with the rest being POA. Coal combustion OA (CCOA) was the largest primary source, on average accounting for 20-32% of OA, and showed the most significant enhancement during haze episodes. A regional SOA (RSOA) was resolved for the first time which showed a pronounced peak only during the record-breaking haze episode (Ep3) on 12-13 January. The regional contributions estimated based on the steep evolution of air pollutants were found to play dominant roles for the formation of Ep3, on average accounting for 66% of PM1 during the peak of Ep3 with sulfate, CCOA, and RSOA being the largest fractions (>~75%). Our results suggest that stagnant meteorological conditions, coal combustion, secondary production, and regional transport are four main factors driving the formation and evolution of haze pollution in Beijing during wintertime.

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Seven years of measurements of aerosol scattering properties, near the surface, in the southwestern Iberia Peninsula

Cited by 66 publications

References 29 publications

Variability of aerosol optical properties in the Western Mediterranean Basin

Variability of aerosol optical properties in the Western Mediterranean Basin

Thirteen Years of Aerosol Radiative Forcing in Southwestern Iberian Peninsula

Investigation of the sources and evolution processes of severe haze pollution in Beijing in January 2013

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