Increase of Global Albedo Due to Air Pollution

Yamamoto, Giichi; Tanaka, Masayuki

doi:10.1175/1520-0469(1972)029<1405:iogadt>2.0.co;2

Cited by 118 publications

(34 citation statements)

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“…Recently organic aerosols have been suggested as major contributors to visibility impairment in scenic areas of the western U.S. (Macias and White, 1987). As EC absorbs light, it may affect the earth's radiation balance and impact global climate (Yamamoto and Tanaka, 1972;Grassel, 1979). EC also has been investigated for its role in catalyzing the conversion of atmospheric SO, to sulfate (Novakov et al, 1974).…”

Section: Introductionmentioning

confidence: 99%

Particulate Carbon Speciation by MnO₂Oxidation

Fung¹

1990

Aerosol Science and Technology

120

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A selective thermal oxidation method was developed for the speciation of carbonaceous aerosols collected on filters into organic carbon (OC) and elemental carbon (EC). The technique is based on studying the thermal oxidation oi microcrystalline graphite by MnO, as well as various organic compounds. The procedure uses a modified Dohrmann DC-52 carbon analyzer with a flame ionization detector to detect the CO, resulting from the oxidation as methane after catalytic conversion. The results led to the selection of 525°C as the optimal temperature for the oxidation of OC while leaving EC intact. After the organic oxidation, the sample is heated at 850°C, at which EC is oxidized rapidly and completely by MnO,. Carbonates that may be present in either the particles or the filter medium are removed by acidification and heating to -120°C prior to performing the organic and EC measurements. Analysis of split ambient particulate samples in which the OC levels had been reduced by solvent extraction produced EC results statistically the same as the original untreated samples. These results suggest that the speciation is not sensitive to the level of organics in the sample. During the Carbonaceous Species Methods Comparison Study (CSMCS) in which the participants analyzed 20 blind samples, with four being triplicates, this technique yielded results in good agreement with the average results of the participants, with coefficients of variation (CV) derived from the triplicate analysis being 2.1%, 2.6%, and 8.1%, respectively, for total, organic, and elemental carbon.

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Section: Introductionmentioning

confidence: 99%

Particulate Carbon Speciation by MnO₂Oxidation

Fung¹

1990

Aerosol Science and Technology

120

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“…Aerosols suspended in the atmosphere have a potential to affect the radiation budget of the earth and the global climate change through change in their optical properties (Yamamoto and Tanaka, 1972;Coakley et al, 1983;Coakley and Cess, 1985), and through their activity as cloud condensation nuclei (Twomey et al, 1984;Wigley, 1989). Observations and modeling of the optical thickness, size distribution and refractive index of aerosols, and investigation of their spatial and temporal variations are indispensable for an assessment of the influence of aerosols on climate.…”

Section: Introductionmentioning

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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“…According to the theoretical study by Yamamoto and Tanaka (1972), the imaginary part of the refractive index mi*0.03 apparently yields only a very small increase in the planetary albedo of the earthatmosphere system for a surface albedo of As=0.15 with an increase of aerosols. This assessment is consistent with the present observational results for the radiation budget effects of the tropospheric aerosols, the existence of which slightly increased the reflected solar radiation from the lower troposphere-surface system by an average of 5% (or 5W/m2) for the three cases over Tsukuba, as shown in Fig.…”

Section: Summary and Discussionmentioning

confidence: 98%

“…Among these parameters the imaginary part mi of the complex refractive index m*=mr-mii is critically important and the least known parameter. Yamamoto and Tanaka (1972) claimed that under global average conditions, if mi is less than 0.05, the earth-atmosphere system will cool with an increase in turbidity (integrated amount of aerosols), while if mi is greater than 0.05, heating of the system is expected due to an increase in turbidity. A similar evaluation has been followed by Herman and Browning (1975), who showed that the critical value of mi depends on the surface reflectance.…”

Section: Introductionmentioning

confidence: 99%

Aircraft Measurements of the Radiative Effects of Tropospheric

Asano¹

1989

Journal of the Meteorological Society of Japan

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The size distribution and the complex refractive index of tropospheric aerosols have been retrieved from the simultaneous observations of solar radiation and aerosols described in Part I of this study (Asano and Shiobara, 1989). Three sets of observations over the Tsukuba area have been analyzed, for which the aerosol optical thicknesses were available from ground-based spectral attenuation measurements of direct solar radiation.The bimodal size distribution for tropospheric aerosols was approximated by a composite powerlaw distribution function. The parameters of the distribution function were determined by fitting the function to the columnar size distributions inverted from photometrically measured spectral optical thicknesses. Estimation was made of wavelength-mean effective values of the complex refractive index m*=mr-mii which optimally simulate the observed solar fluxes and heating rates for the total solar spectral region. In the simulated calculations, the observed profiles of aerosols and water vapor were considered. The single scattering properties were computed from Mie theory for the determined size distribution and for a reasonably assumed real part of the index of refraction of mr=1.52. The optimal value of mi=0.03*0.02 was estimated for the imaginary part of the index of refraction of the tropospheric aerosols.

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Increase of Global Albedo Due to Air Pollution

Cited by 118 publications

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Particulate Carbon Speciation by MnO₂Oxidation

Particulate Carbon Speciation by MnO₂Oxidation

Aerosol Monitoring Using a Scanning Spectral Radiometer in Sendai, Japan

Aircraft Measurements of the Radiative Effects of Tropospheric

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Increase of Global Albedo Due to Air Pollution

Cited by 118 publications

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Particulate Carbon Speciation by MnO2Oxidation

Particulate Carbon Speciation by MnO2Oxidation

Aerosol Monitoring Using a Scanning Spectral Radiometer in Sendai, Japan

Aircraft Measurements of the Radiative Effects of Tropospheric

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Particulate Carbon Speciation by MnO₂Oxidation

Particulate Carbon Speciation by MnO₂Oxidation