Airborne Measurements of Optical Properties of Tropospheric Aerosols over an Urban Area

Tanaka, Masayuki; Hayasaka, Tadahiro; Nakajima, Teruyuki

doi:10.2151/jmsj1965.68.3_335

Cited by 25 publications

(8 citation statements)

References 32 publications

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“…We measured these bimodal distributions over the height range of the measurement between 0.6 and 5.5 km. The bimodal size distributions have frequently been observed in the troposphere over around Japan [Tanaka et al, 1990;Hayasaka et al, 1998]. Our results of the chemical analyses showed that the bimodal shapes were composed primarily of sulfates in the fine mode and mineral dusts and/or sea salts in the coarse mode.…”

Section: Particle Size Distribution and Number Concentrationsupporting

confidence: 59%

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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Section: Particle Size Distribution and Number Concentrationsupporting

confidence: 59%

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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“…The most signi® cant discrepancies appear in the function minimum, which decreases when the value assigned to the imaginary part of m increases. These results are similar to those obtained by Tanaka et al (1990 ) who found that uncertainties in the retrieved t a l due to the uncertainty in the ® xed refractive index are lower than 10%.…”

Section: Inversion Resultssupporting

confidence: 91%

Retrieval of the aerosol size distribution from spectroradiometer measurements at a coastal site in the Mediterranean Sea

Martínez‐Lozano¹,

Utrillas²,

Tena³

1999

International Journal of Remote Sensing

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Values of aerosol optical depth, t a l , have been obtained from spectral irradiance measurements registered at Valencia (Spain) between July 1993 and June 1995. Aerosol size distribution functions were calculated by considering these t a l values and by using the inversion method proposed by King. The results show that such functions are bimodal, with a primary mode that is not apparent and a clearly de® ned secondary mode in the range 0.5± 0.8 mm. Generally, the shape of the distribution function does not depend on the complex refractive index m assigned to the aerosols, although an increase in the imaginary part of m produces a decrease in the function's minimum.

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“…The contribution of the background stratospheric aerosol amount to the total amount is so small that almost all of the columnar aerosols consist of tropospheric aerosols for the periods except the El Chichon event. For example, Ta (500) of stratospheric aerosols for the non-El Chichon periods is about 0.02 or less (Nakajima et al, 1986a;Tanaka et al, 1990) so that the contribution of the background stratospheric aerosols to the columnar total aerosols is expected to be small.…”

Section: B the El Chichon Aerosolsmentioning

confidence: 99%

“…The accumulation mode aerosols are usually found in the planetary boundary layer, while coarse-particle mode aerosols are found in and above the planetary boundary layer. Cress, 1981, 1983;Tanaka et al, 1990;Hayasaka et al, 1990). It is, therefore, reasonable to infer that the accumulation mode aerosols of summer are substances of surface origin, and grow by condensation and coagulation under high temperature and abundant water vapor conditions.…”

Section: B the El Chichon Aerosolsmentioning

confidence: 99%

Aerosol Monitoring Using a Scanning Spectral Radiometer in Sendai, Japan

Shiobara¹,

Hayasaka

Nakajima

et al. 1991

Journal of the Meteorological Society of Japan

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Measurements of direct solar irradiance and sky radiance were carried out in Sendai, Japan for the period from September 1981 to May 1985 using a scanning spectral radiometer (aureolemeter). Size distributions of columnar total aerosols were retrieved by inverting both spectral optical thickness and solar aureole radiance data.The size distribution of aerosols due to the El Chichon eruption in 1982 was estimated as the difference between columnar volume spectra before and after the eruption. The results indicate that the El Chichon aerosol had a monomodal volume spectrum with a mode radius about 0.5 ,*m; their contribution to the total aerosol volume reached the maximum in the winter of 1983, i. e. December 1982 to February 1983, then gradually decaying to the normal level prior to the eruption by the spring of 1985.A seasonal model of tropospheric aerosols over Sendai was constructed by subtracting the volume spectrum of the El Chichon aerosol model from that of the columnar total aerosols, and successfully represented by a bimodal log-normal function. The aerosols in spring and summer seasons have different features in respect of volume spectra. The coarse particle mode aerosols with radii around 3 *m are predominant in spring while the accumulation mode aerosols with radii around 0.2µm are predominant in summer.

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Airborne Measurements of Optical Properties of Tropospheric Aerosols over an Urban Area

Cited by 25 publications

References 32 publications

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

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

Retrieval of the aerosol size distribution from spectroradiometer measurements at a coastal site in the Mediterranean Sea

Aerosol Monitoring Using a Scanning Spectral Radiometer in Sendai, Japan

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