On the characterization of aerosols using the Ångström exponent in the Athens area

Kaskaoutis, D. G.; Kambezidis, H. D.; Adamopoulos, A.D.; Kassomenos, Pavlos

doi:10.1016/j.jastp.2006.07.008

Cited by 55 publications

(31 citation statements)

References 52 publications

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“…The relatively small value of c suggests that Malargüe has a large component of coarse-mode aerosols. This is consistent with physical expectations and other measurements in desert-like environments [42,59].…”

Section: Wavelength Dependencesupporting

confidence: 93%

A study of the effect of molecular and aerosol conditions in the atmosphere on air fluorescence measurements at the Pierre Auger Observatory

Abraham

Abreu

Aglietta

et al. 2010

Astroparticle Physics

131

133

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a b s t r a c tThe air fluorescence detector of the Pierre Auger Observatory is designed to perform calorimetric measurements of extensive air showers created by cosmic rays of above 10 18 eV. To correct these measurements for the effects introduced by atmospheric fluctuations, the Observatory contains a group of monitoring instruments to record atmospheric conditions across the detector site, an area exceeding 3000 km 2 . The atmospheric data are used extensively in the reconstruction of air showers, and are particularly important for the correct determination of shower energies and the depths of shower maxima. This paper contains a summary of the molecular and aerosol conditions measured at the Pierre Auger Observatory since the start of regular operations in 2004, and includes a discussion of the impact of these measurements on air shower reconstructions. Between 10 18 and 10 20 eV, the systematic uncertainties due to all atmospheric effects increase from 4% to 8% in measurements of shower energy, and 4 g cm À2to 8 g cm À2 in measurements of the shower maximum.

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Section: Wavelength Dependencesupporting

confidence: 93%

A study of the effect of molecular and aerosol conditions in the atmosphere on air fluorescence measurements at the Pierre Auger Observatory

Abraham

Abreu

Aglietta

et al. 2010

Astroparticle Physics

131

133

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“…Moderate to high AE values have previously been reported for some regions of India by Sing et al (2010). In summer the DAE values approach zero or are negative, but in the spring both negative and positive DAEs have been reported (Kaskaoutis et al, 2006(Kaskaoutis et al, , 2007. In our findings, Fig.…”

Section: Dae Vs Aodsupporting

confidence: 75%

Classification of Aerosols in an Urban Environment on the Basis of Optical Measurements

Alam

Shaheen

Blaschke

et al. 2016

Aerosol Air Qual. Res.

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The present study investigates various types of aerosol in the Lahore city of Pakistan using Aerosol Robotic Network (AERONET) data over a six year period from 2007 to 2012. Aerosol optical depths (AODs) observed was in the range 0.2-1.12. An analysis of seasonal variations in AOD has indicated that the highest AOD values occurred in summer and the lowest in winter. The urban aerosols of the study area were classified on the basis of optical parameters such as AOD, Extinction Angstrom Exponent (EAE), Absorption Angstrom Exponent (AAE), Single Scattering Albedo (SSA), Asymmetry Parameter (ASY) and Refractive Index (RI). The AAE values were in the range from 0.25 to 3.2. Real Refractive Index (RRI) and Imaginary part of the Refractive Index (IRI) values were in the range from 1.5 to 1.6 and 0 to 0.005 respectively. The major contributions to the atmospheric aerosols over Lahore were from urban industrial emissions, fossil fuel burning and road/soil dust. Higher RRI values reflected larger re-suspended road dust particles and long-range transported particles, while lower values reflected increased anthropogenic absorbing carbonaceous aerosols over the area. The AERONET retrieved SSA (0.80-0.89) and ASY (0.70-0.83) values suggested a predominance of urban industrial, vehicular and dust aerosols over Lahore. The Derivative of Angstrom Exponent (DAE) was derived at a wavelength of 500 nm and was found to indicate a predominance of fine aerosols across all seasons, particularly during summer and autumn seasons. Back-trajectory analyses using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model revealed that the major air masses over Lahore originated from India, Iran and Afghanistan.

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“…Positive values of a′ indicate the dominance of fine/accumulation-mode aerosol particles while negative values of a′ suggest the relative dominance of coarse-mode aerosol particles in the bimodal aerosol size distribution. More details on a′ can be found in several previous studies Reid et al, 1999;O'Neill et al, 2001aO'Neill et al, , 2001bO'Neill et al, , 2002Schuster et al, 2006;Kaskaoutis et al, 2006aKaskaoutis et al, , 2006bBeegum et al, 2009;Soni et al, 2010].…”

Section: Derivatives Of the Angstrom Wavelengthmentioning

confidence: 99%

Aerosol climatology at Delhi in the western Indo‐Gangetic Plain: Microphysics, long‐term trends, and source strengths

et al. 2013

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[1] We present the climatology of aerosol microphysics, its trends, and impact of potential sources based on the long term measurements (for a period of 11.5 years from December 2001 to May 2012) of aerosol optical depths (AOD) in the spectral range 340-1020 nm from an urban center Delhi (28.6 N, 77.3 E, 238 m mean sea level) in the western Indo-Gangetic Plain (IGP). The study is the first ever long-term characterization of aerosols over the western IGP from the ground-based measurements. AODs are known to affect the air quality, visibility, radiative balance, and cloud microphysics of the region and IGP is one of the highest populated and polluted regions of the world. Our measurements show consistently high AOD during the entire period of observation. The seasonal variations of spectral AODs and Angstrom parameters are generally consistent every year. The AODs show a weak but statistically significant (in 95% confidence level) decreasing trend approximately À0.02/year at 500 nm, possibly, modulated by the pre-monsoon heavy dust loading during the first half of the observation period. The climatological monthly mean AOD at shorter wavelengths peaks twice, during June and November, while at longer wavelengths it shows only one peak in June. The annual variations of Angstrom exponent, a and its derivative, a′ suggest the prevalence of multi-modal aerosol size distributions at Delhi. The coarse-mode aerosols dominate during summer (March-June) and monsoon (July-September) seasons, whereas fine/accumulation mode enhances during post-monsoon (October-November) and winter (December-February) seasons. Potential advection pathways have been identified using concentration weighted trajectory (CWT) analysis of the 5 day isentropic air mass back trajectories at the observation site and their seasonal variations are discussed.

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On the characterization of aerosols using the Ångström exponent in the Athens area

Cited by 55 publications

References 52 publications

A study of the effect of molecular and aerosol conditions in the atmosphere on air fluorescence measurements at the Pierre Auger Observatory

A study of the effect of molecular and aerosol conditions in the atmosphere on air fluorescence measurements at the Pierre Auger Observatory

Classification of Aerosols in an Urban Environment on the Basis of Optical Measurements

Aerosol climatology at Delhi in the western Indo‐Gangetic Plain: Microphysics, long‐term trends, and source strengths

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