Evaluation of the aerosol forcing efficiency in the UV erythemal range at Granada, Spain

Antón, Manuel; Gil, J. E.; Fernández‐Gálvez, J.; Lyamani, H.; Valenzuela, Abel; Foyo-Moreno, I.; Olmo, F.J.; Alados-Arboledas, L.

doi:10.1029/2011jd016112

Cited by 36 publications

(32 citation statements)

References 57 publications

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“…In fact, the lowest values of daily ARF at TOA corresponded to the lowest monthly values of the single scattering albedo for those months (Valenzuela et al, 2012a). This result is in agreement with the works of Di Biagio et al (2009) and Antón et al (2011) who showed that the single scattering albedo has a large influence on the daily ARF. The small values of the forcing at TOA during those months and the corresponding high values at the surface mean that less solar energy reached the ground and more energy was absorbed by atmosphere.…”

Section: Annual Evolution Of Aerosol Radiative Forcingsupporting

confidence: 82%

Aerosol radiative forcing during African desert dust events (2005–2010) over Southeastern Spain

et al. 2012

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Abstract. The daily (24 h) averages of the aerosol radiative forcing (ARF) at the surface and the top of the atmosphere (TOA) were calculated during desert dust events over Granada (southeastern Spain) from 2005 to 2010. A radiative transfer model (SBDART) was utilized to simulate the solar irradiance values (0.31-2.8 µm) at the surface and TOA, using as input aerosol properties retrieved from CIMEL sun photometer measurements via an inversion methodology that uses the sky radiance measurements in principal plane configuration and a spheroid particle shape approximation. This inversion methodology was checked by means of simulated data from aerosol models, and the derived aerosol properties were satisfactorily compared against well-known AERONET products. Good agreement was found over a common spectral interval (0.2-4.0 µm) between the simulated SBDART global irradiances at surface and those provided by AERONET. In addition, simulated SBDART solar global irradiances at the surface have been successfully validated against CM-11 pyranometer measurements. The comparison indicates that the radiative transfer model slightly overestimates (mean bias of 3 %) the experimental solar global irradiance. These results show that the aerosol optical properties used to estimate ARF represent appropriately the aerosol properties observed during desert dust outbreak over the study area. The ARF mean monthly values computed during desert dust events ranged from −13 ± 8 W m −2 to −34 ± 15 W m −2 at surface, from −4 ± 3 W m −2 to −13 ± 7 W m −2 at TOA and from +6 ± 4 to +21 ± 12 W m −2 in the atmosphere. We have checked if the differences found in aerosol optical properties among desert dust sectors translate to differences in ARF. The mean ARF at surface (TOA) were −20 ± 12 (−5 ± 5) W m −2 , −21 ± 9 (−7 ± 5) W m −2 and −18 ± 9 (−6 ± 5) W m −2 for sector A (northern Morocco; northwestern Algeria), sector B (western Sahara, northwestern Mauritania and southwestern Algeria), and sector C (eastern Algeria, Tunisia), respectively. The Kolmogorov-Smirnov statistical test revealed that daily ARF values at TOA for sector A were significantly different from the other two sectors, likely as a result of the lower values of single scattering albedo obtained for sector A. The mean values of aerosol radiative forcing efficiency at surface (TOA) were −74 ± 12 W m −2 (−17 ± 7 W m −2 ) for sector A, −70 ± 14 W m −2 (−20 ± 9 W m −2 ) for sector B, and −65 ± 16 W m −2 (−22 ± 10 W m −2 ) for sector C, and thus comparable between the three sectors in all seasons.

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Section: Annual Evolution Of Aerosol Radiative Forcingsupporting

confidence: 82%

Aerosol radiative forcing during African desert dust events (2005–2010) over Southeastern Spain

et al. 2012

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“…7. Furthermore, the influence of mineral dust aerosol (with high aerosol optical depth) during these months also causes strong radiative effects, as was also reported by previous studies (e.g., Cachorro et al, 2008;Guerrero-Rascado et al, 2009;Antón et al, 2011;Román et al, 2013;García et al, 2014). In addition, the bimodality of the monthly AOD climatology mentioned in Section 4 has its impact on the radiative effects.…”

Section: Inter-annual and Intra-annual Evolution Of Aresupporting

confidence: 58%

“…The AFE is a function of the aerosol optical properties, where both the aerosol particle size distribution and absorptive properties play a key role (e.g., Antón et al, 2011). As we assumed a fixed value of SSA = 0.90 in the simulations with AOD 440 nm < 0.15 (see Table 2), the AFE is calculated only for those cases showing AOD 440 nm larger than 0.15.…”

Section: Aerosol Radiative Forcing Efficiency In Different Spectral Rmentioning

confidence: 99%

Aerosol radiative effects in the ultraviolet, visible, and near-infrared spectral ranges using long-term aerosol data series over the Iberian Peninsula

et al. 2014

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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, longterm 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 (ARE UV ), visible (ARE VIS ), near-infrared (ARE NIR ), and the entire SW range (ARE SW ) under cloudfree conditions. Over the whole Iberian Peninsula, yearly aerosol radiative effects in the different spectral ranges were found to be −1.1 < ARE UV < −0.7, −5.7 < ARE VIS < −3.5, −2.6 < ARE NIR < −1.6, and −8.8 < ARE SW < −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 AFE VIS /AFE SW and AFE NIR /AFE SW . The AFE VIS was the dominant contributor for all aerosol types, although non-absorbing large particles caused more even contribution of VIS and NIR intervals. The AFE UV / AFE SW ratio showed a higher value in the case of absorbing fine particles.

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“…This will shine a new light on the influence of the aerosols on the UV radiation at Uccle. Antón et al (2011) already reported that it is hard to determine the effect of aerosols due to their temporal and spatial variability and the difficulties associated with their characterization.…”

Section: Seasonal Mlr Analysis Using Total Ozone Column Global Solarmentioning

confidence: 99%

Relations between erythemal UV dose, global solar radiation, total ozone column and aerosol optical depth at Uccle, Belgium

et al. 2014

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Abstract. At Uccle, Belgium, a long time series of simultaneous measurements of erythemal ultraviolet (UV) dose (S ery ), global solar radiation (S g ), total ozone column (Q O 3 ) and aerosol optical depth (τ aer ) (at 320.1 nm) is available, which allows for an extensive study of the changes in the variables over time. Linear trends were determined for the different monthly anomalies time series. S ery , S g and Q O 3 all increase by respectively 7, 4 and 3 % per decade. τ aer shows an insignificant negative trend of −8 % per decade. These trends agree with results found in the literature for sites with comparable latitudes. A change-point analysis, which determines whether there is a significant change in the mean of the time series, is applied to the monthly anomalies time series of the variables. Only for S ery and Q O 3 , was a significant change point present in the time series around February 1998 and March 1998, respectively. The change point in Q O 3 corresponds with results found in the literature, where the change in ozone levels around 1997 is attributed to the recovery of ozone. A multiple linear regression (MLR) analysis is applied to the data in order to study the influence of S g , Q O 3 and τ aer on S ery . Together these parameters are able to explain 94 % of the variation in S ery . Most of the variation (56 %) in S ery is explained by S g . The regression model performs well, with a slight tendency to underestimate the measured S ery values and with a mean absolute bias error (MABE) of 18 %. However, in winter, negative S ery are modeled. Applying the MLR to the individual seasons solves this issue. The seasonal models have an adjusted R 2 value higher than 0.8 and the correlation between modeled and measured S ery values is higher than 0.9 for each season. The summer model gives the best performance, with an absolute mean error of only 6 %. However, the seasonal regression models do not always represent reality, where an increase in S ery is accompanied with an increase in Q O 3 and a decrease in τ aer . In all seasonal models, S g is the factor that contributes the most to the variation in S ery , so there is no doubt about the necessity to include this factor in the regression models. The individual contribution of τ aer to S ery is very low, and for this reason it seems unnecessary to include τ aer in the MLR analysis. Including Q O 3 , however, is justified to increase the adjusted R 2 and to decrease the MABE of the model.

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Evaluation of the aerosol forcing efficiency in the UV erythemal range at Granada, Spain

Cited by 36 publications

References 57 publications

Aerosol radiative forcing during African desert dust events (2005–2010) over Southeastern Spain

Aerosol radiative forcing during African desert dust events (2005–2010) over Southeastern Spain

Aerosol radiative effects in the ultraviolet, visible, and near-infrared spectral ranges using long-term aerosol data series over the Iberian Peninsula

Relations between erythemal UV dose, global solar radiation, total ozone column and aerosol optical depth at Uccle, Belgium

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