Vertical distribution of atmospheric particles and water vapor densities in the free troposphere: Lidar measurement in spring and summer in Nagoya, Japan

Kwon, Soung-An; Iwasaka, Yasunobu; Shibata, Takashi; Sakai, Tetsu

doi:10.1016/s1352-2310(96)00310-x

Cited by 30 publications

(29 citation statements)

References 24 publications

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“…The third elevated layer, above about 4 km, is characterized by depolarization ratio values greater than 20 %. The dust layers between 2 and 4 km height and above 4 km height have been observed and identified as dust aerosol layers with different origin, from the Gobi and Taklimakan deserts respectively (Kwon et al, 1997;Matsuki et al, 2003).…”

Section: Conditional Dust Extinction Coefficientmentioning

confidence: 99%

Nine-year spatial and temporal evolution of desert dust aerosols over South and East Asia as revealed by CALIOP

et al. 2018

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Abstract. We present a 3-D climatology of the desert dust distribution over South and East Asia derived using CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) data. To distinguish desert dust from total aerosol load we apply a methodology developed in the framework of EARLINET (European Aerosol Research Lidar Network). The method involves the use of the particle linear depolarization ratio and updated lidar ratio values suitable for Asian dust, applied to multiyear CALIPSO observations (January 2007-December 2015. The resulting dust product provides information on the horizontal and vertical distribution of dust aerosols over South and East Asia along with the seasonal transition of dust transport pathways. Persistent high D_AOD (dust aerosol optical depth) values at 532 nm, of the order of 0.6, are present over the arid and semi-arid desert regions. Dust aerosol transport (range, height and intensity) is subject to high seasonality, with the highest values observed during spring for northern China (Taklimakan and Gobi deserts) and during summer over the Indian subcontinent (Thar Desert). Additionally, we decompose the CALIPSO AOD (aerosol optical depth) into dust and non-dust aerosol components to reveal the nondust AOD over the highly industrialized and densely populated regions of South and East Asia, where the non-dust aerosols yield AOD values of the order of 0.5. Furthermore, the CALIPSO-based short-term AOD and D_AOD time series and trends between January 2007 and December 2015 are calculated over South and East Asia and over selectedPublished by Copernicus Publications on behalf of the European Geosciences Union. 1338 E. Proestakis et al.: Nine-year spatial and temporal evolution of desert dust aerosols subregions. Positive trends are observed over northwest and east China and the Indian subcontinent, whereas over southeast China trends are mostly negative. The calculated AOD trends agree well with the trends derived from Aqua MODIS (Moderate Resolution Imaging Spectroradiometer), although significant differences are observed over specific regions.

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Section: Conditional Dust Extinction Coefficientmentioning

confidence: 99%

Nine-year spatial and temporal evolution of desert dust aerosols over South and East Asia as revealed by CALIOP

et al. 2018

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“…Many lidar measurements made in Japan have shown that the long-range transport of KOSA particles is extremely active in the free troposphere over East Asia and west Pacific regions in the spring Kwon et al, 1997;Sakai et al, 2000;Murayama et al, 2001), and the Taklamakan Desert has been suggested as a major source of KOSA particles.…”

Section: Introductionmentioning

confidence: 99%

Feature of Dust Particles in the Spring Free Troposphere over Dunhuang in Northwestern China: Electron Microscopic Experiments on Individual Particles Collected with a Balloon-borne Impactor

Yamada

Iwasaka

Matsuki

et al. 2005

Water Air Soil Pollut: Focus

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Free tropospheric aerosol particles were collected using a balloon-borne particle impactor in August of 2002 and March of 2003 at Dunhuang in northwestern China (40 • 00 N, 94 • 30 E), and the morphology and elemental composition of the aerosol particles were analyzed in order to understand the mixing state of coarse dust particles (diameter >1 µm) over the desert areas in the Asian continent in spring. Electron microscopic experiments on the particles revealed that dust particles were major constituents of coarse mode particles in the free troposphere over the Taklamakan Desert in spring and summer.Si-rich or Ca-rich particles are major components of dust particles collected in the free troposphere over Dunhuang and the values of [number of Ca-rich particles]/[number of Si-rich particles] differs markedly between spring and summer, being about 0.3 in the spring of 2003 and about 1.0 in the summer of 2002 at heights 3-5 km above sea level. It is likely that the condition of the ground surface and the strength of vertical mixing in source areas of Asian dust are potential factors causing the difference in the chemical types of dust particles.Comparison of the elemental compositions of these particles with those of particles collected over Japan strongly suggests that these particles were chemically modified during their long-range transport in the free troposphere. Analysis of wind systems shows that both the predominating westerly wind in the free troposphere and the surface wind strongly controlled by the geographical structure of the Tarim Basin are important in the long-range transport of KOSA particles originating in the Taklamakan Desert.

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“…Using this technique, Kwon et al [1997] and Sakai et al [2000] have shown that the depolarization ratio in the free troposphere is generally high (>10%) over a wide range of relative humidities in the spring over Nagoya in Japan, probably due to the transport of mineral dust particles from the Asian arid regions. Because the depolarization ratio is a measure of particle nonsphericity [e.g., Bohren and Huffman, 1983], it can be utilized to detect mineral dust particles since they are mostly nonspherical [e.g., Okada et al, 1987Okada et al, , 2001.…”

Section: Introductionmentioning

confidence: 99%

Raman lidar and aircraft measurements of tropospheric aerosol particles during the Asian dust event over central Japan: Case study on 23 April 1996

et al. 2003

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[1] The vertical distributions of tropospheric aerosol properties were measured during the Asian dust event over central Japan (35°-36°N, 136°-137°E), using a ground-based Raman lidar and aircraft-based instruments on 23 April 1996. The lidar measured enhancements of aerosol backscattering below an altitude of 4 km and between 5 and 8 km where the total aerosol linear depolarization ratio showed peaks of 12-15% and the relative humidities were $30%. The aircraft measurements showed that the aerosol particles consisted primarily of irregularly shaped mineral dusts and sea salts with a mode radius (r m ) of $1 mm and sulfates with r m $ 0.1 mm over the measured height range of 0.6-5.5 km. Electron microscopic analyses suggest that $77% of the mineral particles were coated with a solution at 1.8 km and that the fraction of coated particles decreased with height. The aerosol backscattering coefficients (b a ), calculated from the airborne optical particle counter (OPC) data, were smaller than the lidar-derived values by $30% above 3.1 km and by $44% below that altitude. The difference was attributable to the horizontal and temporal inhomogeneities of the aerosol properties between the measurement sites and to the uncertainty in b a , particularly for the coarse particles calculated from the OPC data. The aerosol depolarization ratios (d a ) estimated from the OPC data showed the same increase as those obtained with the lidar above 4.1 km. This suggests that the proportion of backscattering by coarse particles to total particles primarily controlled the d a measured with the lidar in that region.

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Vertical distribution of atmospheric particles and water vapor densities in the free troposphere: Lidar measurement in spring and summer in Nagoya, Japan

Cited by 30 publications

References 24 publications

Nine-year spatial and temporal evolution of desert dust aerosols over South and East Asia as revealed by CALIOP

Nine-year spatial and temporal evolution of desert dust aerosols over South and East Asia as revealed by CALIOP

Feature of Dust Particles in the Spring Free Troposphere over Dunhuang in Northwestern China: Electron Microscopic Experiments on Individual Particles Collected with a Balloon-borne Impactor

Raman lidar and aircraft measurements of tropospheric aerosol particles during the Asian dust event over central Japan: Case study on 23 April 1996

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