An assessment of hygroscopic growth factors for aerosols in the surface boundary layer for computing direct radiative forcing

Im, Jung-Sun; Saxena, V. K.; Wenny, Brian N.

doi:10.1029/2000jd000152

Cited by 59 publications

(42 citation statements)

References 44 publications

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“…Though the optical attenuation method has shown excellent agreement with other analytic methods (Allen et al, 1999;Im et al, 2001) and has been widely used Beegum et al, 2009;Babu et al, 2011), there are several reports available in recent literature on the uncertainties related to the estimation of EBC by aethelometer (e.g., Weingartner et al, 2003;Arnott et al, 2005;Corrigan et al, 2006). From different literature, it is clear that all the available methods for measurement of EBC mass concentration are based on some assumptions that are instrument specific, site specific and also depends on the type of carbonaceous aerosol, and its fraction to the total aerosol mass (Weingartner et al, 2003;Hitzenberger et al, 2006;Moorthy et al, 2007;Nair et al, 2007).…”

Section: Instrumentation (Measurement Data)mentioning

confidence: 91%

Seasonal Characteristics of Aerosol Black Carbon in Relation to Long Range Transport over Tripura in Northeast India

Guha

Dhar

et al. 2015

Aerosol Air Qual. Res.

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This study presents the characteristics of aerosol black carbon (BC) from a rural continental site, Agartala, located in the North-Eastern part of India using two year measurements from September 2010 to September 2012. Diurnal and seasonal variations are examined in relation to the unique geographical location, changeable meteorological conditions and distinct source characteristics. Winter season is characterized by extremely high BC concentration (17.8 ± 9.2 µg/m 3 ) comparable to those seen in urban environments of India, dropping off to much lower values during the monsoon (2.8 ± 1.7 µg/m 3 ). Even this lowest seasonal mean is rather high, given the rural nature of Tripura. Examination of the spectral dependence of aerosol absorption coefficients indicates that the main source of aerosol to total BC burden at Agartala is the fossil fuel combustions. Concentration weighted trajectory (CWT) analysis indicate that the characteristic high BC during winter is mostly associated with the advection from the Indo-Gangetic Plains (IGP), while the air mass pattern is constricted to the oceanic region during monsoon making BC aloft due to local pollution only.

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Section: Instrumentation (Measurement Data)mentioning

confidence: 91%

Seasonal Characteristics of Aerosol Black Carbon in Relation to Long Range Transport over Tripura in Northeast India

Guha

Dhar

et al. 2015

Aerosol Air Qual. Res.

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“…The correlation between extinction coefficient ka and PM10 is also affected by the chemical components of particles and relative humidity of the air, since the PM10 concentrations measured by the instruments are almost the dry mass of the particles with aerodynamic diameter less than 10 μm. Thus, f (RH) is used to define the hygroscopic growing factor as [36,45]:…”

Section: Jan 5 Janmentioning

confidence: 99%

Retrieval of High-Resolution Atmospheric Particulate Matter Concentrations from Satellite-Based Aerosol Optical Thickness over the Pearl River Delta Area, China

Yang

Wang

2015

Remote Sensing

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Satellite remote sensing offers an effective approach to estimate indicators of air quality on a large scale. It is critically significant for air quality monitoring in areas experiencing rapid urbanization and consequently severe air pollution, like the Pearl River Delta (PRD) in China. This paper starts with examining ground observations of particulate matter (PM) and the relationship between PM10 (particles smaller than 10 μm) and aerosol optical thickness (AOT) by analyzing observations on the sampling sites in the PRD. A linear regression (R 2 = 0.51) is carried out using MODIS-derived 500 m-resolution AOT and PM10 concentration from monitoring stations. Data of atmospheric boundary layer (ABL) height and relative humidity are used to make vertical and humidity corrections on AOT. Results after correction show higher correlations (R 2 = 0.55) between extinction coefficient and PM10. However, coarse spatial resolution of meteorological data affects the smoothness of retrieved maps, which suggests high-resolution and accurate meteorological data are critical to increase retrieval accuracy of PM. Finally, the model provides the spatial distribution maps of instantaneous and yearly average PM10 over the PRD. It is proved that observed PM10 is more relevant to yearly mean AOT than instantaneous values.

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“…Figure 5 shows an example of this feature. Hygroscopic growth of aerosols and the consequent effects on aerosol light scattering can be assumed to be essentially negligible under such dry conditions (Nemesure et al, 1995;Baumgardner and Clarke, 1998;Im et al, 2001;Redemann et al, 2001;Carrico et al, 2003;Markowicz et al, 2003). Thus, the optical properties of aerosols measured near the surface are likely to be similar to those aloft in a well-mixed boundary layer, which is advantageous for some radiative closure analyses.…”

Section: Instrumentsmentioning

confidence: 99%

The T1-T2 study: evolution of aerosol properties downwind of Mexico City

et al. 2007

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Abstract. As part of a major atmospheric chemistry and aerosol field program carried out in March 2006, a study was conducted in the area to the north and northeast of Mexico City to investigate the evolution of aerosols and their associated optical properties in the first few hours after their emission. The focus of the T1-T2 aerosol study was to investigate changes in the specific absorption α ABS (absorption per unit mass, with unit of m 2 g −1 ) of black carbon as it aged and became coated with compounds such as sulfate and organic carbon, evolving from an external to an internal mixture. Such evolution has been reported in previous studies. The T1 site was located just to the north of the Mexico City metropolitan area; the T2 site was situated approximately 35 km farther to the northeast. Nephelometers, particle soot absorption photometers, photoacoustic absorption spectrometers, and organic and elemental carbon analyzers were used to measure the optical properties of the aerosols and the carbon concentrations at each of the sites. Radar wind profilers and radiosonde systems helped to characterize the meteorology and to identify periods when transport from Mexico City over T1 and T2 occurred. Organic and elemental carbon concentrations at T1 showed diurnal cycles reflecting the nocturnal and early morning buildup from nearby sources, while concentrations at T2 appeared to be more affected by transport from Mexico City. Specific absorption during transport periods was lower than during other times, consistent with the likelihood of fresher emissions being found when the winds blew from Mexico City over T1 and T2. The speCorrespondence to: J. C. Doran (christopher.doran@pnl.gov) cific absorption at T2 was larger than at T1, which is also consistent with the expectation of more aged particles with encapsulated black carbon being found at the more distant location. In situ measurements of single scattering albedo with an aircraft and a ground station showed general agreement with column-averaged values derived from rotating shadowband radiometer data, although some differences were found that may be related to boundary-layer evolution.

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An assessment of hygroscopic growth factors for aerosols in the surface boundary layer for computing direct radiative forcing

Cited by 59 publications

References 44 publications

Seasonal Characteristics of Aerosol Black Carbon in Relation to Long Range Transport over Tripura in Northeast India

Seasonal Characteristics of Aerosol Black Carbon in Relation to Long Range Transport over Tripura in Northeast India

Retrieval of High-Resolution Atmospheric Particulate Matter Concentrations from Satellite-Based Aerosol Optical Thickness over the Pearl River Delta Area, China

The T1-T2 study: evolution of aerosol properties downwind of Mexico City

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