scholarly journals Change of iron species and iron solubility in Asian dust during the long-range transport from western China to Japan

2011 ◽  
Vol 11 (21) ◽  
pp. 11237-11252 ◽  
Author(s):  
Y. Takahashi ◽  
M. Higashi ◽  
T. Furukawa ◽  
S. Mitsunobu
Keyword(s):  
Long Range ◽  
Asian Dust ◽  
Western China ◽  
Long Range Transport ◽  
Chemical Extraction ◽  
Iron Species ◽  
Iron Solubility ◽  
X Ray ◽  
Soluble Iron ◽  
Range Transport

Abstract. In the North Pacific, transport and deposition of mineral dust from Asia appear to be one of major sources of iron which can regulate growth of phytoplankton in the ocean. In this process, it is essential to identify chemical species of iron contained in Asian dust, because bioavailability of iron in the ocean is strongly influenced by the solubility of iron, which in turn is dependent on iron species in the dust. Here, we report that clay minerals (illite and chlorite) in the dusts near the source collected at Aksu (western China) can be transformed into ferrihydrite by atmospheric chemical processes during their long-range transport to eastern China (Qingdao) and Japan (Tsukuba) based on the speciation by X-ray absorption fine structure (XAFS) and other methods such as X-ray diffraction and chemical extraction. As a result, Fe molar ratio in Aksu (illite : chlorite : ferrihydrite = 70 : 25 : 5) was changed to that in Tsukuba (illite : chlorite : ferrihydrite = 65 : 10 : 25). Moreover, leaching experiments were conducted to study the change of iron solubility. It was found that the iron solubility for the dust in Tsukuba (soluble iron fraction: 11.8 % and 1.10 % for synthetic rain water and seawater, respectively) was larger than that in Aksu (4.1 % and 0.28 %, respectively), showing that iron in the dust after the transport becomes more soluble possibly due to the formation of ferrihydrite in the atmosphere. Our findings suggested that secondary formation of ferrihydrite during the transport should be considered as one of important processes in evaluating the supply of soluble iron to seawater.

scholarly journals Change of iron species and iron solubility in Asian dust during the long-range transport from western China to Japan

2011 ◽  
Vol 11 (7) ◽  
pp. 19545-19580 ◽  
Author(s):  
Y. Takahashi ◽  
M. Higashi ◽  
T. Furukawa ◽  
S. Mitsunobu
Keyword(s):  
Clay Minerals ◽  
Long Range ◽  
Mineral Dust ◽  
Asian Dust ◽  
Western China ◽  
Long Range Transport ◽  
Chemical Extraction ◽  
Iron Species ◽  
X Ray ◽  
Range Transport

Abstract. In the North Pacific, transport and deposition of mineral dust from Asia appear to be one of major sources of iron which can regulate growth of phytoplankton in the ocean. In this process, it is essential to identify chemical species of iron contained in Asian dust, because bioavailability of iron in the ocean is strongly influenced by the solubility of iron, which in turn is dependent on iron species in the dust. Here, we report that clay minerals (illite and chlorite) in the dusts near the source (western China) are transformed into ferrihydrite by atmospheric chemical processes during their long-range transport to eastern China and Japan based on the speciation by X-ray absorption fine structure (XAFS) and other methods such as X-ray diffraction and chemical extraction. Moreover, it was found that iron in the dust after the transport becomes more soluble in our leaching experiments conducted for 24 h compared with those for initial dusts possibly due to the formation of ferrihydrite in the atmosphere. Our findings suggested that ferrihydrite secondarily formed during the transport is an important source of soluble iron species, which can be more soluble than clay minerals initially contained in the mineral dust such as illite and chlorite.

scholarly journals Spectral optical properties of long-range transport Asian dust and pollution aerosols over Northeast Asia in 2007 and 2008

2010 ◽  
Vol 10 (12) ◽  
pp. 5391-5408 ◽  
Author(s):  
J. Jung ◽  
Y. J. Kim ◽  
K. Y. Lee ◽  
M. G. -Cayetano ◽  
T. Batmunkh ◽  
...  
Keyword(s):  
Optical Properties ◽  
Long Range ◽  
Atmospheric Chemistry ◽  
Light Attenuation ◽  
Measurement Data ◽  
Absorption Efficiency ◽  
Asian Dust ◽  
Urban Site ◽  
Long Range Transport ◽  
Range Transport

Abstract. As a part of the IGAC (International Global Atmospheric Chemistry) Mega-cities program, aerosol physical and optical properties were continuously measured from March 2007 to March 2008 at an urban site (37.57° N, 126.94° E) in Seoul, Korea. Spectral optical properties of long-range transported Asian dust and pollution aerosols have been investigated based on the year long measurement data. Optically measured black carbon/thermally measured elemental carbon (BC/EC) ratio showed clear monthly variation with high values in summer and low values in winter mainly due to the enhancement of light attenuation by the internal mixing of EC. Novel approach has been suggested to retrieve the spectral light absorption coefficient (babs) from Aethalometer raw data by using BC/EC ratio. Mass absorption efficiency, σabs (=babs/EC) at 550 nm was determined to be 9.0±1.3, 8.9±1.5, 9.5±2.0, and 10.3±1.7 m2 g−1 in spring, summer, fall, and winter, respectively with an annual mean of 9.4±1.8 m2 g−1. Threshold values to classify severe haze events were suggested in this study. Increasing trend of aerosol single scattering albedo (SSA) with wavelength was observed during Asian dust events while little spectral dependence of SSA was observed during long-range transport pollution (LTP) events. Satellite aerosol optical thickness (AOT) and Hysplit air mass backward trajectory analyses as well as chemical analysis were performed to characterize the dependence of spectral optical properties on aerosol type. Results from this study can provide useful information for studies on regional air quality and aerosol's effects on climate change.

scholarly journals Temporal trend and sources of speciated atmospheric mercury at Waliguan GAW station, northwestern China

2011 ◽  
Vol 11 (11) ◽  
pp. 30053-30089 ◽  
Author(s):  
X. W. Fu ◽  
X. Feng ◽  
P. Liang ◽  
H. Zhang ◽  
J. Ji ◽  
...  
Keyword(s):  
Long Range ◽  
Temporal Trend ◽  
Ambient Air ◽  
Atmospheric Mercury ◽  
Western China ◽  
Long Range Transport ◽  
Gaseous Mercury ◽  
Sampling Campaign ◽  
Regional Sources ◽  
Range Transport

Abstract. Measurements of speciated atmospheric mercury were conducted at a remote mountain-top station (WLG) at the edge of northeastern part of the Qinghai-Xizang Plateau, western China. Mean concentrations of total gaseous mercury (TGM), particulate mercury (PHg), and reactive gaseous mercury (RGM) during the whole sampling campaign were 1.98 ± 0.98 ng m−3, 19.4 ± 18.1 pg m−3, and 7.4 ± 4.8 pg m−3, respectively. Levels of speciated Hg at WLG were slightly higher than those reported from remote areas of North America and Europe. Both regional emissions and long-rang transport played a remarkable role in the distribution of TGM and PHg in ambient air at WLG, whereas RGM showed major links to the regional sources, likely as well as the in-situ productions by photochemical processes. Regional sources for speciated Hg were mostly located to the east of WLG, which is the most developed areas of Qinghai province and accounted for most of the province's anthropogenic Hg emissions. Potential source contribution function (PSCF) results showed a strong impact of long-range transport from eastern Gansu, western Ningxia and Shanxi Province, with good accordance with locations of urban areas and industrial centers. Moreover, we found that northern India was also an important source region of WLG during the sampling campaign, and this is the first time of direct evidence of long-range transport of atmospheric Hg from India to northeastern Tibetan Plateau. Seasonal and diurnal variations of TGM were in contrast with most of the previous studies in China, with relatively higher levels in warm seasons and night, respectively. The temporal trend of TGM also highlighted the impact of long-range transport on the distribution of TGM in ambient air at WLG.

scholarly journals Asian Long-Range Transport in Relation to Atmospheric Rivers in Northern California

Atmosphere ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 313
Author(s):  
Catherine N. Liu ◽  
Sen Chiao ◽  
Ju-Mee Ryoo
Keyword(s):  
Long Range ◽  
Cold Season ◽  
Asian Dust ◽  
Long Range Transport ◽  
Back Trajectory ◽  
Northern California ◽  
Atmospheric Rivers ◽  
Back Trajectory Analysis ◽  
Range Transport ◽  
Moderate Resolution Imaging Spectroradiometer

The study investigates the effect of aerosol long-range transport on precipitation over Northern California during atmospheric river (AR) events in the 2017 cold season (January–April). ARs in 2017 were one of the strongest to date, and the intense precipitation associated with the ARs resulted in flooding, destruction of property, and contamination of water supplies. The Aerosol Optical Depth (AOD) from Moderate Resolution Imaging Spectroradiometer (MODIS) data shows Asian dust traveling across the Northern Pacific Ocean along with AR events. Aerosol measurements in California, provided by the Interagency Monitoring of Protected Visual Environments (IMPROVE), show that more Asian dust tends to be observed over the coast, while non-Asian/localized dust is observed inland. A mixture of Asian and localized dust is observed over the mountains, although higher amounts of both are observed in the spring (March–April). Back trajectory analysis confirms that Asian aerosols are transported along the air parcels, and each AR event has its own transport pattern in terms of horizontal advection and vertical lifting. Correlation between precipitation and aerosols is low. This suggests that aerosols contribute little to the decrease of local precipitation during the 2017 AR events.

Long-range transport of Asian dust to the Lower Fraser Valley, British Columbia, Canada

2001 ◽  
Vol 106 (D16) ◽  
pp. 18361-18370 ◽  
Author(s):  
I. G. McKendry ◽  
J. P. Hacker ◽  
R. Stull ◽  
S. Sakiyama ◽  
D. Mignacca ◽  
...  
Keyword(s):  
British Columbia ◽  
Long Range ◽  
Asian Dust ◽  
Long Range Transport ◽  
Range Transport ◽  
Lower Fraser Valley ◽  
Fraser Valley

scholarly journals Long-term monitoring of atmospheric total gaseous mercury (TGM) at a remote site in Mt. Changbai area, northeastern China

2012 ◽  
Vol 12 (2) ◽  
pp. 4417-4446 ◽  
Author(s):  
X. W. Fu ◽  
X. Feng ◽  
L. H. Shang ◽  
S. F. Wang ◽  
H. Zhang
Keyword(s):  
Long Range ◽  
Northeastern China ◽  
Western China ◽  
Long Range Transport ◽  
Remote Site ◽  
Total Gaseous Mercury ◽  
Large Power ◽  
Gaseous Mercury ◽  
Regional Sources ◽  
Range Transport

Abstract. Total gaseous mercury (TGM) was continuously monitored at a remote site (CBS) in the Mt. Changbai area, northeastern China biennially from 24 October 2008 to 31 October 2010. The overall mean TGM concentration was 1.60 ± 0.51 ng m−3, which is lower than those reported from remote sites in eastern, southwestern and western China, indicating a relatively low regional anthropogenic mercury (Hg) emission intensity in northeastern China. Measurements at a site in the vicinity (~1.2 km) of the CBS station during August 2005 and July 2006 showed a significantly higher mean TGM concentration of 3.58 ± 1.78 ng m−3. The divergent result was partially attributed to fluctuations in the regional surface wind system and moreover an effect of local emission sources. The temporal variation of TGM at CBS was obviously influenced by regional sources as well as long-range transported Hg. Regional sources, frequently contributing to episodical high TGM concentrations, were pinpointed as a large iron mining district in northern North Korea and two large power plants and urban areas to the southwest of the sampling site. Source areas in Beijing, Tianjin, southern Liaoning, Hebei, northwestern Shanxi and northwestern Shandong were found to contribute to elevated TGM observations at CBS via long-range transport. The diurnal pattern of TGM at CBS was mainly regulated by regional sources, likely as well as intrusion of air masses from the free troposphere during summer season. There are no discernible seasonal pattern of TGM at CBS, which mainly showed links with the patterns of regional air movements and long-range transport.

scholarly journals Two years of measurements of atmospheric total gaseous mercury (TGM) at a remote site in Mt. Changbai area, Northeastern China

2012 ◽  
Vol 12 (9) ◽  
pp. 4215-4226 ◽  
Author(s):  
X. W. Fu ◽  
X. Feng ◽  
L. H. Shang ◽  
S. F. Wang ◽  
H. Zhang
Keyword(s):  
Long Range ◽  
Northeastern China ◽  
Western China ◽  
Long Range Transport ◽  
Remote Site ◽  
Total Gaseous Mercury ◽  
Large Power ◽  
Gaseous Mercury ◽  
Regional Sources ◽  
Range Transport

Abstract. Total gaseous mercury (TGM) was continuously monitored at a remote site (CBS) in Mt. Changbai area, Northeastern China from 24 October 2008 to 31 October 2010. The overall mean TGM concentration was 1.60±0.51 ng m−3, which is lower than those reported from remote sites in Eastern, Southwestern, and Western China, indicating a relatively lower regional anthropogenic mercury (Hg) emission intensity in Northeastern China. Measurements at a site in the vicinity (~1.2 km) of CBS station from August 2005 to July 2006 showed a significantly higher mean TGM concentration of 3.58±1.78 ng m−3. The divergent result was partially attributed to fluctuations in the relatively frequencies of surface winds during the two study periods and moreover an effect of local emission sources. The temporal variation of TGM at CBS was influenced by regional sources as well as long-range transported Hg. Regional sources frequently contributing to episodical high TGM concentrations were pin-pointed as a large iron mining district in Northern North Korea and two large power plants and urban areas to the southwest of the sampling site. Source areas in Beijing, Tianjin, southern Liaoning, Hebei, northwestern Shanxi, and northwestern Shandong were found to contribute to elevated TGM observations at CBS via long-range transport. Diurnal pattern of TGM at CBS was mainly controlled by regional sources, likely as well as intrusion of air masses from the free troposphere during summer season. There are no consistent seasonal pattern of TGM at CBS, and the monthly TGM variations showed links with the patterns of regional air movements and long-range transport.

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