記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi:10.1029/2012GL053890

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi:10.1038/NGEO583

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi:10.1029/2008GL035630

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： doi:10.1117/12.806540

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi:10.1029/2007GL032329

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi:10.1029/2007GL030338

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi:10.1029/2005JD006575

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2151/jmsj.83A.219

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Mass concentrations of chemical compounds in both PM_2.5 (particle aerodynamic diameter, Dp < 2.5 μm) and PM_2.5-10 (2.5 < Dp < 10 μm), and acidity of aerosol particles were measured at an urban site in western Japan using a continuous dichotomous Aerosol Chemical Speciation Analyzer (ACSA-12) throughout 2014. Mass concentrations of both PM_2.5 and sulfate had distinct seasonal variabilities with maxima in spring and winter, mostly due to long-range transport with the prevailing westerly wind. Mass concentration of nitrate in PM_2.5 (fNO₃) showed an obvious warm-season-low and cold-season-high pattern as a result of both gas-aerosol phase equilibrium processes under high temperature conditions as well as transport. Nitrate in PM_2.5-10 (cNO₃) increased during long-range transport of dust, implying the great importance of heterogeneous processes at the surface of coarse mode particles. In this study, Δ[H⁺] (derived from the difference in pH of extract liquid with/without sampling) was used to indicate the acidity of particles. We found that acidity of particles in PM_2.5 (fΔH) was mostly positive with a maximum in August because of the large fraction of nitrate and sulfate. Acidity of particles in PM_2.5-10 (cΔH) was negative in winter and spring due to presence of alkaline matter from crustal sources. This study highlights the great importance of anthropogenic pollutants on the acidity of particles in the western Pacific Ocean and further impact on the marine environment and climate. Meteorology and transport played a key role in the allocation of aerosol phase nitrate in PM_2.5, PM_2.5-10. Seasonal variability of acidity of PM_2.5 was mainly attributed to fraction of water-soluble secondary inorganics and source regions.

DOI： 10.1016/j.envpol.2017.11.089

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Long-term synergetic fine and coarse mode aerosol observations were analyzed at 1-h intervals at Fukuoka, Japan, from January to June 2015. The GEOS-Chem chemical transport model, including dust and sea-salt acid uptake processes, was used for detailed analysis of observation data. Several Asian dust events and long-range anthropogenic aerosol transport events were observed during our analysis period, and the numerical model generally explained the observed time variation for both fine and coarse mode aerosols. We found that (i) the majority of fine mode NO₃ ^– can be considered as long-range transport (LRT) outside of Japan during the cold season, and (ii) the peak timing of fine mode NO₃ ^– coincided with that of SO₄ ^–, indicating that both aerosols are controlled by LRT. Also, an observed mass concentration ratio of NO₃ ^–/SO₄ ^2– > 0.9 occurred during the cold season, indicating the importance of NO₃ ^– as a major contributor to the PM_2.5 mass fraction. Finally, we clearly showed that large-scale dust-nitrate outflow from China to Fukuoka was confirmed in all cases of dust events, indicating that the anthropogenic NO_x is converted to dust-nitrate and transported to Japan with dust. These results demonstrate the importance of anthropogenic NO₃ ^– LRT during the cold season and dust-nitrate LRT for all dust events (even in June).

DOI： 10.4209/aaqr.2016.11.0494

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We analyzed long-term fine- and coarse-mode synergetic observations of nitrate and related aerosols (SO2 4 , NO3 , NHC4 , NaC, Ca2C) at Fukuoka (33.52 N, 130.47 E) from August 2014 to October 2015. A Goddard Earth Observing System chemical transport model (GEOS-Chem) including dust and sea salt acid uptake processes was used to assess the observed seasonal variation and the impact of long-range transport (LRT) from the Asian continent. For fine aerosols (fSO2 4 , fNO3 , and fNHC4 ), numerical results explained the seasonal changes, and a sensitivity analysis excluding Japanese domestic emissions clarified the LRT fraction at Fukuoka (85% for fSO2 4 , 47% for fNO3 , 73% for fNHC4 ). Observational data confirmed that coarse NO3 (cNO3 ) made up the largest proportion (i.e., 40-55 %) of the total nitrate (defined as the sum of fNO3 , cNO3 , and HNO3) during the winter, while HNO3 gas constituted approximately 40% of the total nitrate in summer and fNO3 peaked during the winter. Large-scale dust-nitrate (mainly cNO3 ) outflow from China to Fukuoka was confirmed during all dust events that occurred between January and June. The modeled cNO3 was in good agreement with observations between July and November (mainly coming from sea salt NO3 ). During the winter, however, the model underestimated cNO3 levels compared to the observed levels. The reason for this underestimation was examined statistically using multiple regression analysis (MRA).We used cNaC, nsscCa2 C, and cNHC4 as independent variables to describe the observed cNO3 levels; these variables were considered representative of sea salt cNO3 , dust cNO3 , and cNO3 accompanied by cNHC4 ), respectively. The MRA results explained the observed seasonal changes in dust cNO3 and indicated that the dust-acid uptake scheme reproduced the observed dust-nitrate levels even in winter. The annual average contributions of each component were 43% (sea salt cNO3 ), 19% (dust cNO3 ), and 38% (cNHC4 term). The MRA dust-cNO3 component had a high value during the dust season, and the sea salt component made a large contribution throughout the year. During the winter, cNHC4 term made a large contribution. The model did not include aerosol microphysical processes (such as condensation and coagulation between the fine anthropogenic aerosols NO3 and SO2 4 and coarse particles), and our results suggest that inclusion of aerosol microphysical processes is critical when studying observed cNO3 formation, especially in winter.

DOI： 10.5194/acp-17-14181-2017

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Ground-based observation of the polarization properties of aerosol particles using a polarization optical particle counter (POPC) was made from 27 October 2013, to 31 December 2015, at a suburban site in the Kyushu area of Japan. We found that the depolarization ratio (DR, the fraction of s-polarized signal in the total backward light scattering signal) of aerosol particles showed prominent seasonal variability, with peaks in spring (0.21-0.23) and winter (0.19-0.23), and a minimum value (0.09-0.14) in summer. The aerosol compositions in both fine mode (aerodynamic diameter of particle, D_p < 2.5 μm) and coarse mode (2.5 μm < D_p < 10 μm), and the size-dependent polarization characteristics were analyzed for long-range transport dust particles, sea salt, and anthropogenic pollution-dominant aerosols. The DR value increased with increasing particle size, and DR= 0.1 was a reliable threshold value to identify the sphericity of supermicron (Dp > 1 μm) particles. Occurrence of substandard air quality days in Kyushu was closely related with mixed type (coexistence of anthropogenic pollutants and dust particles in the atmosphere), especially in winter and spring, indicating that dust events in the Asian continent played a key role in the cross-boundary transport of continental pollution. Backward trajectory analysis demonstrated that air masses originating from the western Pacific contained large amounts of spherical particles due to the influence of sea salt, especially in summer; however, for air masses from the Asian continent, the dependence of number fraction of spherical particles on air relative humidity was insignificant, indicating the predominance of less-hygroscopic substances (e.g., mineral dust), although the mass concentrations of anthropogenic pollutants were elevated.

DOI： 10.5194/acp-16-9863-2016

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi:10.1002/ 2015GL067589

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Asian dust has a significant impact on the natural environment. Its variability on multiple timescales modulates the ocean biogeochemistry and climate. We demonstrate that temporal changes in the deposition flux of Aeolian dust recorded in sediments from Lake Suigetsu, central Japan, during the last century exhibit a continuous decreasing trend and a decadal-scale decrease in 1952-1974. The former decreasing trend can be explained by a decrease in the dust storm frequency at source regions due to the warming of Mongolia in the twentieth century, suggesting future decrease of Asian dust transport with further warming in Mongolia. Decadal-scale decrease of Aeolian dust is explained by weaker westerlies in lower latitudes in central Japan, reflecting a weaker Aleutian Low during the corresponding period. Decadal-scale westerly change probably causes north-south shifts of the dominant dust transport path, which affects subarctic northern Pacific Ocean biogeochemistry by changing the micronutrient iron supply.

DOI： 10.1002/2015GL067589

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi:10.5194/acp-2015-904

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We observed a long-lasting dust event from 25 May to 2 June 2014, using a polarization optical particle counter (POPC). The transport of dust plumes over East Asia was verified on the basis of observations of Moderate Resolution Imaging Spectroradiometer, a lidar network, and surface synoptic observation stations. Mixing of dust and anthropogenic pollutants was investigated according to the variation in the depolarization ratio as a function of particle size. The nonsphericity of dust particles varied due to the impact of anthropogenic pollutants on their pathway. In the coarse mode, dust particles always had a clear nonspherical configuration, although large amounts of nitrate were also present. Supermicron particles are occasionally present in a spherical configuration, possibly due to the complex mixing of natural dust and anthropogenic particles. Statistically, ~64% of the total nitrate mass was deemed to be transported from outside of Japan due to a trapping effect in the dust plume.

DOI： 10.1002/2014GL062491

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Record heavy PM_2.5 air pollution (maximum concentration of ∼1 mg m^-3) observed over China in January 2013 was analyzed. The vertical and horizontal scales of the pollution layer are critically important parameters for the analysis of pollution phenomena, but they are difficult to measure. This is because the PM_2.5 aerosol concentration is so high that ordinary remote-sensing methods such as ground-based and space-borne lidar inversion are difficult to apply. First, we showed the detailed time-height structure of aerosol extinction coefficients based on Beijing lidar observation, by assuming a non-zero boundary extinction coefficient and using 3D chemical transport modeling (CTM). The aerosol structure derived from lidar observations and the CTM results were in close agreement. Using ground-based lidar, we also found that a shallow aerosol layer (height of 200-300 m) remained over Beijing for a long time. We also successfully showed that the horizontal extent of the aerosol layer over the China Plain was several hundred km based on CALIOP observations and CTM.

DOI： 10.2151/sola.2014-028

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The Asian dust events in 2008 (May 24-June 4 in 2008) and in 2009 (March 12-25, October 13-26, and December 15-28 in 2009) were analyzed with the lidar network observations, surface observations in China, Korea, Japan, and Mongolia, and with the chemical transport model CFORS. Transport of Asian dust and mixing of dust with air pollution aerosols were studied. The event of May 24 to June 4 in 2008 was a significant event unusually late in the spring dust season. The dust event of March 12-25, 2009 was an interesting example of elevated dust layer, and transport of dust from the elevated dust layer to the ground by the boundary layer activity was observed with the lidars and surface observations in Japan. The concentration of air pollution aerosols was relatively high during the dust event, and the results suggest that vertical structure as well as transport path is important for the mixing of dust and air pollution aerosols. The dust events in October and December 2009 were examples of dust events in autumn and winter. The online mode CFORS reproduced the observation data generally well, except for the event of May 24 to June 4 in 2008. The results of the fourdimensional variational assimilation of the lidar network data reproduced the dust concentration in Korea and Japan reasonably in that event.

DOI： 10.1007/s13143-013-0004-3

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We expanded the variational assimilation system of a regional dust model by using size-resolved inversion. Dust emissions and particle-size distributions of a severe dust and sandstorm (DSS) in April 2005 were inversely optimized with optical measurements by the National Institute for Environmental Studies lidar network. The inversion results successfully compensated underestimates by the original model and increased the ngstrm exponent around the DSS core by 13-17%, shifting the particle-size distribution to finer. The a posteriori size distribution was distinctly different between eastern and western source regions. In the western regions, dust emissions in the 3.19 and 5.06 m size bins increased considerably, and the peak size shifted from 5.06 to 3.19 m, whereas in the eastern regions, emissions of finer particles (bins 0.82-2.01 m) increased. Differences in vegetation and soil type and moisture between eastern and western regions might explain the characteristics of the inverted size distribution.

DOI： 10.1029/2012GL053890

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The NASA space-borne Mie-lidar system CALIPSO/CALIOP revealed that multiple large Asian dust layers with a horizontal scale of 2000-3000 km reached North America, occupying the full troposphere, in April 2010. This kind of dust layer transport has not been reported before. Our analysis of CALIOP data and global aerosol model results revealed that frequent dust emissions occurred in northwestern China because of stronger-than-average near-surface winds, and that strong stable westerly winds carried the Asian dust from northwestern China to the central Pacific Ocean. A negative pressure anomaly was located in the eastern Pacific Ocean, and the main dust transport path was split into two branches: a northern path and a southern path over North America. Northern-path dust was trapped and stagnant for a longer time than southern path dust and finally subsided under a high-pressure system. Dust along the southern path reached the central US. These complex conditions resulted in a multi-layered structure of dust over North America.

DOI： 10.5194/acp-11-7333-2011

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Surface observation data taken in Mongolia, China, Korea and Japan during the Asian dust event of March 29 to April 2, 2007 were compared with a regional dust transport model assimilated with the lidar network data. The assimilated model reproduced the reported dust event in Mongolia and the observed PM10 concentrations in Korea and Japan very well. The mass/extinction conversion factor (MEF) obtained from the lidar dust extinction coefficient and PM10 concentration was also compared with the assimilated model for Seoul and Tsukuba where both the lidar and PM10 data were available. The MEFs for PM10 and PM2.5 (the ratio of dust-only PM10 or PM2.5 to the dust extinction coefficient) were calculated with the assimilated model. The modeled MEF for PM10 reproduced the observed MEF reasonably and exhibited spatial and temporal variations reflecting the variations in the dust particle size distribution. The modeled MEF for PM2.5 had much less variation. This indicates that the dust extinction coefficient has a higher correlation with dust PM2.5 and should be a useful index for studying the effect of dust on human health.

DOI： 10.2151/sola.7A-004

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Seasonal characteristics of spherical aerosol distributions in eastern Asia were investigated between July 2006 and December 2008 using data from ground-based and space-borne lidar observations and the Community Multi-scale Air Quality Modeling System (CMAQ) chemical transport model simulation. The seasonal variation of spherical aerosol optical thickness (AOT) observed at four ground lidar stations surrounding the East China Sea (Beijing, Guangzhou, Seoul, and Hedo/Okinawa) was generally consistent with CMAQ simulation results. Detailed analyses confirmed clear regional differences in aerosol compositions. Analyses of aerosol vertical profiles revealed that the spherical aerosol variation is greatest in Beijing, with scale height varying between 720 m and 2100 m. The analyses also revealed that the seasonal variation patterns of spherical AOT are classifiable into 'summer peak' and 'summer trough' types. Northern sites (Beijing and Seoul) are of the summer peak type; southern sites (Guangzhou and Okinawa) show the summer trough pattern. Our analyses demonstrated that the Asian summer-winter monsoon system plays a major role in regulating such seasonal variation. The CMAQ simulated variation of spherical aerosols is well correlated to the synoptic scale monsoon variation.

DOI： 10.2151/sola.2011-031

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

This paper presents the results of recent studies on tropospheric aerosols, including Asian dust and forest fire smoke using the NIES Lidar Network, CALIPSO/CALIOP and chemical transport models. The NIES Lidar Network is a network of two-wavelength (532nm, 1064nm) polarization (532nm) lidars in East Asia. Currently the lidars are continuously operated at about 20 locations in Japan, Korea, China, Mongolia, and Thailand, in cooperation with various research institutes and universities. The network is a part of the Asian Dust Network (ADNet), SKYNET, and the GAW Aerosol Lidar Observation Network (GALION). The data from most of the lidar stations are transferred to NIES in realtime and automatically processed to derive the attenuated backscattering coefficients at 532nm and 1064nm, the volume depolarization ratio at 532nm, and the estimated dust and spherical aerosol extinction coefficients at 532nm. The data from the network are used in various research activities on Asian dust, regional air pollution, and the effects of aerosols on climate and the environment. The data are also used for real-time monitoring (for early warning assessment) of Asian dust. The results of recent studies on long-range transport of Asian dust, optical characteristics of forest fire plumes, aerosol climatology, etc. will be described.

DOI： 10.1117/12.869900

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Springtime outflow of Asian dust and air pollutants was investigated by a synergetic analysis of ground-based/space-borne Lidar observations and numerical models. We identified two prominent outflow patterns, and its occurrence frequency. Pattern I was induced within a typical warm-sector which lifted up dust particles into the free troposphere, and the existence of two sequential low-pressure systems played an important role. Pattern II was a behind cold front outbreak. Atmospheric stratification was significantly different; Pattern I had weak stratification within the troposphere (potential temperature gradient of ∼2-3.4 K/km), and most of elevated dust layer (typically horizontally 1500-2000 km, vertically 2.5-4 km AGL) remained unmixed with pollutants. Pattern II was characterized by a strong stratification of ∼5 K/km; dust and pollutants were trapped and well mixed within the PBL, forming polluted dust. Among the six cases of large-scale dust/pollutants outbreaks, only two cases are belonged to Pattern I.

DOI： 10.1029/2010GL044776

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Dust emission estimated with a 4D-Var data assimilation system using ground-based lidar network data was compared with vegetation growth data based on visual observations in the Gobi desert in Mongolia in the spring of 2007. The dust emission flux estimated with the data assimilation system was less than that estimated without data assimilation in the dust event of May 21-30 and was the opposite in the event of March 25-April 3. The threshold surface friction velocity estimated from the results of the data assimilation was less than 0.3 m s^-1 in the dust event of March 25-April 3 and was ~0.36 m s^-1 in the event of May 21-30. The difference between the two events was qualitatively explained by the vegetation growth data. The accumulated precipitation during the period was ~2 mm. The results show that vegetation growth with slight precipitation in the Gobi desert may significantly reduce dust emission.

DOI： 10.2151/sola.2010-032

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Mineral dust is usually transported long distances in the lower troposphere. There are examples of Asian dust being transported across the Pacific Ocean, and traces of Asian dust have also been found in ice and snow cores in Greenland and the French Alps. Here, we use measurements from the Cloud-Aerosol Lidar with Orthogonal Polarization, an air parcel trajectory model and a three-dimensional aerosol transport model to map the transport of dust clouds generated during a storm in Chinas Taklimakan Desert during May 2007. We show that the dust-veiled clouds were lofted to the upper troposphere around 8-10 km above the Earths surface and transported more than one full circuit around the globe in about 13 days. When the dust reached the northwestern Pacific Ocean for the second time, the subsidence of a large-scale high-pressure system caused it to descend into the lower troposphere; some of the dust was then deposited over the ocean. Our analysis also indicates that the dust particles may have acted as ice nuclei in these high-altitude clouds, leading to the formation of cirrus clouds. We suggest that Asian dust can influence the global radiation budget by stimulating cirrus cloud formation and marine ecosystems by supplying nutrients to the open ocean.

DOI： 10.1038/ngeo583

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Three-dimensional structures of Asian dust transport in the planetary boundary layer (PBL) and free atmosphere occurring successively during the end of May 2007 were clarified using results of space-borne backscatter lidar, Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), and results obtained using a data-assimilated version of a dust transport model (RC4) based on a groundbased NIES lidar network. The dust layer depths and the vertical and horizontal structure simulated by RC4 agreed with those of CALIOP observations from the dust source region to the far-downstream region. Two important transport mechanisms of Asian dust in the PBL and free atmosphere were clarified: a low-level dust outbreak within the dry slot region of a well-developed low-pressure system, and formation of an elevated dust layer within the warm sector of a low-pressure system. We also represent the aging of pure dust particles using the particle depolarization ratio (PDR) at 532 nm and the color ratio (CR) at 1064 nm and 532 nm. Aerosols with high PDR were observed uniformly over the dust source region. While the dust cloud was transported to the eastern downwind regions, aerosols with low PDR and high CR occur in the layer of less than 1 km height, suggesting a mixing state of spherical aerosols and dust in the surface layer.

DOI： 10.5194/acp-9-1227-2009

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

Observations of tropospheric aerosols (mineral dust, air-pollution aerosols, etc.) and clouds are being conducted using a network of two-wavelength (1064nm, 532nm) polarization (532nm) lidars in the East Asian region. Currently, the lidars are operated continuously at 23 locations in Japan, Korea, China, Mongolia and Thailand. A real-time data processing system was developed for the network, and the data products such as the attenuated backscatter coefficients and the estimated extinction coefficients for non-spherical and spherical aerosols are generated automatically for online network stations. The data are used in the real-time monitoring of Asian dust as well as in the studies of regional air pollution and climate change.

DOI： 10.1117/12.806540

開催年月日： 2014年1月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡県　福岡市   国名：日本国  

開催年月日： 2014年1月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡県　春日市   国名：日本国  

開催年月日： 2013年3月

会議種別：口頭発表（一般）  

開催地：長崎歴史文化博物館   国名：日本国  

開催年月日： 2013年1月

会議種別：口頭発表（一般）  

開催地：九州大学　応用力学研究所   国名：日本国  

開催年月日： 2012年11月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Fukuoka, Japan   国名：日本国  

記述言語：英語   会議種別：シンポジウム・ワークショップ パネル（公募）  

開催地：SanFrancisco   国名：アメリカ合衆国  

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Castellaneta Marina   国名：イタリア共和国  

記述言語：英語   会議種別：口頭発表（一般）  

国名：中華人民共和国  

記述言語：日本語   会議種別：シンポジウム・ワークショップ パネル（公募）  

国名：日本国  

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：春日市   国名：日本国  

開催年月日： 2012年10月

会議種別：シンポジウム・ワークショップ パネル（公募）  

開催地：Chapel Hill, North Carolina   国名：アメリカ合衆国  

Recent rapid economic growth of Eastern Asian countries has caused a marked increase of anthropogenic emission (Ohara et al., 2007) since 2000. However, Lu et al. (2011) reported that SO2 emission in China decreased by 9.2% from 2006 to 2010 due to the wide application of flue-gas desulfurization (FGD) devices in power plants. On the other hand, Lamsal et al. (2011) showed that NOx emission from East Asia increased by 18.8 % during 2006-2009. Anthropogenic emission in East Asia has changed dramatically by the balance between economic development and political emission control. National Institute for Environmental Studies (NIES) has been constructing a ground-based network of automated dual-wavelength (532, 1064 nm), polarization-sensitive (532 nm) Mie-lidar systems to examine air quality continuously in eastern Asia since 2001 (Shimizu et al., 2004). In this paper, recent inter-annual trend of anthropogenic aerosols was investigated using ground-based lidar data, space-borne lidar, the Moderate resolution Imaging Spectroradiometer (MODIS) data and the Community Multi-scale Air Quality Modeling System (CMAQ) chemical transport model simulation during 2004-2011. The increase trend of spherical aerosol optical depth (AOD) was observed over the wide region of East Asia by aerosol retrievals of lidar and MODIS from 2004 to 2008. After 2008, the decrease trend of AOD was seen in downwind region (around Japan), while increase trend of AOD was still observed in northeastern China by remote sensing. CMAQ showed that the main composition of spherical aerosol around Japan is sulfate, therefore recent AOD decrease trend in downwind region may be basically caused by the SO2 emission reduction due to the FGD devices in China. The AOD increase trend in northeastern China might be attributed by increase of secondary aerosol formed from precursor species including NOx after 2008.

開催年月日： 2012年10月

会議種別：シンポジウム・ワークショップ パネル（公募）  

開催地：北海道大学   国名：日本国  

記述言語：日本語  

記述言語：日本語  

記述言語：日本語