Aerosol optical, chemical and physical properties at Gosan, Korea during Asian dust and pollution episodes in 2001

Kim, Sang Woo; Yoon, Soon‐Chang; Jefferson, Anne; Ogren, J. A.; Dutton, Ellsworth G; Won, Jong-Seob; Ghim, Young Sung; Lee, Byung-Il; Han, Jin-Seok

doi:10.1016/j.atmosenv.2004.09.056

Cited by 99 publications

(48 citation statements)

References 24 publications

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“…According to the AOD~FMF classification method by Barnaba and Gobbi (2004), who conclude that the aerosols with AOD (550 nm) ≤ 0.3 and FMF < 0.8 are considered to be marine type, AOD (550 nm) > 0.3 and FMF < 0.7 for dust, and all the other aerosols are considered of continental type (AOD (550 nm) < 0.3 and FMF > 0.8, or AOD (550 nm) > 0.3 and FMF ≥ 0.7), and AOD~α classification method by Dubovik et al (2002), the dominant aerosols in the southern part of East China (excluding the Poyang Lake plain) are mostly emitted from natural source and possibly consist of continental and marine types, and the dominant aerosols over the northern part of East China are emitted from natural source and anthropogenic source and possibly consist of soil dust, biomass burning and urban/industrial type. The aerosols from natural source (such as soil dust) are possibly connected to the windblown mineral dust storms that usually occur in the spring (Kim, 2005). Meanwhile, plenty of construction activities due to fast economic development also contributed numerous dust-like particles into the atmosphere.…”

Section: Summary Of Aerosol Distributions In East Chinamentioning

confidence: 99%

Study on Long-term Aerosol Distribution over the Land of East China Using MODIS Data

Geng

et al. 2012

Aerosol Air Qual. Res.

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East China is among the fastest developing area in Asia, where atmospheric aerosol loading is high due to heavy urban and industrial emission. The Moderate Resolution Imaging Spectroradiometer (MODIS) level 2 aerosol products (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) were used to study aerosol spatial and temporal distributions, as well as their variations with local meteorological conditions over East China. By combining Aerosol Optical Depth (AOD) and aerosol Fine Mode Fraction (FMF), we found that the urban/industrial aerosol and soil dust are possibly two dominant species over northern part, whereas continental and marine aerosols possibly dominate the southern part of East China. Both annual mean AOD and area with high AOD increased from 2000 to 2007, with the largest increase seen in Yangtze River Delta region (YRD). In summer, AOD in East China reached the maximum of about 0.8 in YRD, dominated by fine mode particles. The minimum AOD occurred in winter with mostly coarse mode particles. Local aerosol properties were analyzed in three typical zones: the northern dry zone (I), the central urban/industrial zone (II) and the southern natural background zone (III). Monthly mean AODs in zone I and II were above 0.5 throughout the entire year, with the maximum AOD in June. High FMFs in this period indicated heavy urban and industrial pollution. Monthly mean AODs and FMFs in zone III reached maximum of 0.51 in April and September (up to 90.7%) respectively. High AOD in spring in zone III appears mostly due to the long-range dust transport from the North.

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Section: Summary Of Aerosol Distributions In East Chinamentioning

confidence: 99%

Study on Long-term Aerosol Distribution over the Land of East China Using MODIS Data

Geng

et al. 2012

Aerosol Air Qual. Res.

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“…It is not influenced by local pollutant emissions and samples air masses transported downwind of continental Asia (e.g. Kim et al (2005)). Models were also compared to vertical aerosol backscatter signals measured by the Japanese National Institute for Environmental Studies (NIES) ground-based lidar network Sugimoto et al, 2008) covering Japan with 10 lidars cali- brated using a similar procedure.…”

Section: Ground-based Datamentioning

confidence: 99%

“…Instrumentation deployed at the observatory measured ozone, NO x (defined as the sum of NO and NO 2 ) and CO (Chou et al, 2011), as well as particulate matter (PM: PM 2.5 and PM 10 ), organic carbon (OC) and BC (Huang et al, 2010). The Gosan observatory (Kim et al, 2005) is a longterm observatory located on the Jeju Island, South Korea, measuring OC, BC, aerosol number size distributions (Flowers et al, 2010) and NO x , sulphur dioxide ( SO 2 ), CO and ozone concentrations. It is not influenced by local pollutant emissions and samples air masses transported downwind of continental Asia (e.g.…”

Section: Ground-based Datamentioning

confidence: 99%

Multi-model evaluation of short-lived pollutant distributions over east Asia during summer 2008

et al. 2016

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Abstract. The ability of seven state-of-the-art chemistryaerosol models to reproduce distributions of tropospheric ozone and its precursors, as well as aerosols over eastern Asia in summer 2008, is evaluated. The study focuses on the performance of models used to assess impacts of pollutants on climate and air quality as part of the EU ECLIPSE project. Models, run using the same ECLIPSE emissions, are compared over different spatial scales to in situ surface, vertical profiles and satellite data. Several rather clear biases are found between model results and observations, including overestimation of ozone at rural locations downwind of the main emission regions in China, as well as downwind over the Pacific. Several models produce too much ozone over polluted regions, which is then transported downwind. Analysis points to different factors related to the ability of models to simulate VOC-limited regimes over polluted regions and NO x limited regimes downwind. This may also be linked to biases compared to satellite NO 2 , indicating overestimation of NO 2 over and to the north of the northern China Plain emission region. On the other hand, model NO 2 is too low to the south and west of this region and over South Korea/Japan. Overestimation of ozone is linked to systematic underestimation of CO particularly at rural sites and downwind of the main Chinese emission regions. This is likely to be due to enhanced destruction of CO by OH. Overestimation of Asian ozone and its transport downwind impliesPublished by Copernicus Publications on behalf of the European Geosciences Union. With regard to aerosols, most models reproduce the satellite-derived AOD patterns over eastern China. Our study nevertheless reveals an overestimation of ECLIPSE model mean surface BC and sulphate aerosols in urban China in summer 2008. The effect of the short-term emission mitigation in Beijing is too weak to explain the differences between the models. Our results rather point to an overestimation of SO 2 emissions, in particular, close to the surface in Chinese urban areas. However, we also identify a clear underestimation of aerosol concentrations over northern India, suggesting that the rapid recent growth of emissions in India, as well as their spatial extension, is underestimated in emission inventories. Model deficiencies in the representation of pollution accumulation due to the Indian monsoon may also be playing a role. Comparison with vertical aerosol lidar measurements highlights a general underestimation of scattering aerosols in the boundary layer associated with overestimation in the free troposphere pointing to modelled aerosol lifetimes that are too long. This is likely linked to too strong vertical transport and/or insufficient deposition efficiency during transport or export from the boundary layer, rather than chemical processing (in the case of sulphate aerosols). Underestimation of sulphate in the boundary layer implies potentially large errors in simulated aerosol-cloud interactions, via impacts on boundary-layer clouds...

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“…The Ångström exponent (Å) was calculated using linear regres-sion of ln(τ ) vs. ln(λ) (i.e., wavelength) with the data obtained at 380, 440, 500, 675, and 870 nm. These aerosol parameters were used in the column radiative model (CRM) as input data to calculate the aerosol direct radiative forcing and forcing efficiency (Won et al, 2004;Kim et al, 2010). The CRM uses a δ-Eddington approximation with 19 spectral intervals spanning from 0.2 to 5 µm and accounts for several gas absorption spectra; seven spectral bands of O 3 and H 2 O, three of CO 2 , and absorption bands of N 2 O, CH 4 , CFC-11, and CFC-12 are included (Slingo, 1989;Briegleb, 1992).…”

Section: Methodsmentioning

confidence: 99%

Wintertime aerosol optical and radiative properties in the Kathmandu Valley during the SusKat-ABC field campaign

et al. 2017

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Abstract. Particulate air pollution in the Kathmandu Valley has reached severe levels that are mainly due to uncontrolled emissions and the location of the urban area in a bowl-shaped basin with associated local wind circulations. The AERONET measurements from December 2012 to August 2014 revealed a mean aerosol optical depth (AOD) of approximately 0.30 at 675 nm during winter, which is similar to that of the post-monsoon but half of that of the pre-monsoon AOD (0.63). The distinct seasonal variations are closely related to regional-scale monsoon circulations over South Asia and emissions in the Kathmandu Valley. During the SusKat-ABC campaign (December 2012-February 2013, a noticeable increase in both aerosol scattering (σ s ; 313 → 577 Mm −1 at 550 nm) and absorption (σ a ; 98 → 145 Mm −1 at 520 nm) coefficients occurred before and after 4 January 2013. This can be attributed to the increase in wood-burned fires due to a temperature drop and the start of firing at nearby brick kilns. The σ s value in the Kathmandu Valley was a factor of 0.5 lower than that in polluted cities in India. The σ a value in the Kathmandu Valley was approximately 2 times higher than that at severely polluted urban sites in India. The aerosol mass scattering efficiency of 2.6 m 2 g −1 from PM 10 measurements in the Kathmandu Valley is similar to that reported in urban areas. However, the aerosol mass absorption efficiency was determined to be 11 m 2 g −1 from PM 10 measurements, which is higher than that reported in the literature for pure soot particles (7.5 ± 1.2 m 2 g −1 ). This might be due to the fact that most of the carbonaceous aerosols in the Kathmandu Valley were thought to be mostly externally mixed with other aerosols under dry conditions due to a short travel time from their sources. The σ s and σ a values and the equivalent black carbon (EBC) mass concentration reached up to 757 Mm −1 , 224 Mm −1 , and 29 µg m −3 at 08:00 LST (local standard time), respectively but decreased dramatically during the daytime (09:00-18:00 LST), to one-quarter of the morning average (06:00-09:00 LST) due to the development of valley winds and an atmospheric bounder layer. The σ s and σ a values and the EBC concentration remained almost constant during the night at the levels of 410 Mm −1 , 130 Mm −1 , and 17 µg m −3 , respectively. The average aerosol direct radiative forcings over the intensive measurement period were estimated to be −6.9 ± 1.4 W m −2 (top of the atmosphere) and −20.8 ± 4.6 W m −2 (surface). Therefore, the high atPublished by Copernicus Publications on behalf of the European Geosciences Union. 12618 C. Cho et al.: Wintertime aerosol optical and radiative properties in the Kathmandu Valley mospheric forcing (i.e., 13.9 ± 3.6 W m −2 ) and forcing efficiency (74.8 ± 24.2 W m −2 τ −1 ) can be attributed to the high portion of light-absorbing aerosols in the Kathmandu Valley, as indicated by the high black carbon (or elemental carbon) to sulphate ratio (1.5 ± 1.1).

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Aerosol optical, chemical and physical properties at Gosan, Korea during Asian dust and pollution episodes in 2001

Cited by 99 publications

References 24 publications

Study on Long-term Aerosol Distribution over the Land of East China Using MODIS Data

Study on Long-term Aerosol Distribution over the Land of East China Using MODIS Data

Multi-model evaluation of short-lived pollutant distributions over east Asia during summer 2008

Wintertime aerosol optical and radiative properties in the Kathmandu Valley during the SusKat-ABC field campaign

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