Optical properties of the crustal aerosol: Relation to chemical and physical characteristics

Patterson, E. M.

doi:10.1029/jc086ic04p03236

Cited by 95 publications

(72 citation statements)

References 49 publications

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“…The observed absorption is much less than mineral dust models that were constructed from laboratory measurements of Saharan aerosols on filter pads [Patterson, 1981]. These with range of models constructed from laboratory measurements of imaginary refractive index of Saharan aerosol samples.…”

Section: Discussionmentioning

confidence: 99%

Columnar aerosol single‐scattering albedo and phase function retrieved from sky radiance over the ocean: Measurements of Saharan dust

2003

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[1] The single-scattering albedo and phase function of African mineral dust are retrieved at 14 wavelengths across the visible spectrum from ground-based measurements of the aerosol optical thickness and the sky radiance taken in the solar principal plane. The retrieval algorithm employs the radiative transfer equation to solve by iteration for these properties that best reproduce the observed sky radiance, and is therefore independent of particle shape. The estimated error in the retrieved single-scattering albedo is less than 0.02 due to the precision of the solar-reflectance-based calibration of the radiometer. The phase function retrieved at 860 nm is robust under simulations of expected experimental errors and may be used to characterize aerosol scattering at the directly measured scattering angles (i.e., Â 155°). The phase function retrieved at 443 nm, however, is too sensitive to such errors to confidently describe the angular scattering at blue wavelengths. The single-scattering albedo displays a spectral shape expected of iron-bearing minerals but is much higher than climate models have assumed, indicating that wind-blown mineral dust cools Earth more than is generally believed. The method may be applied to any combination of airborne and ground-based measurements over the ocean and can complement more involved ground-based retrievals through its insensitivity to particle shape and ability to retrieve aerosol properties at relatively small aerosol optical depths.INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 1640 Global Change: Remote sensing; 1694 Global Change: Instruments and techniques; 4275 Oceanography: General: Remote sensing and electromagnetic processes (0689); KEYWORDS: aerosol, mineral dust, absorption, sky radiance, scattering, optical properties Citation: Cattrall, C., K. L. Carder, and H. R. Gordon, Columnar aerosol single-scattering albedo and phase function retrieved from sky radiance over the ocean: Measurements of Saharan dust,

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Section: Discussionmentioning

confidence: 99%

Columnar aerosol single‐scattering albedo and phase function retrieved from sky radiance over the ocean: Measurements of Saharan dust

2003

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“…Dust optical properties are based on Patterson (1981), as explained in Zender et al (2003). These dust optical properties, applied globally, are based on measurements of Saharan dust, which may differ from the optical properties of dust from other source regions (Sokolik and Toon, 1999).…”

Section: Constraints On Particle Parametersmentioning

confidence: 99%

Arctic climate response to forcing from light-absorbing particles in snow and sea ice in CESM

Goldenson

Doherty²,

Bitz

et al. 2012

Atmos. Chem. Phys.

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Abstract. The presence of light-absorbing aerosol particles deposited on arctic snow and sea ice influences the surface albedo, causing greater shortwave absorption, warming, and loss of snow and sea ice, lowering the albedo further. The Community Earth System Model version 1 (CESM1) now includes the radiative effects of light-absorbing particles in snow on land and sea ice and in sea ice itself. We investigate the model response to the deposition of black carbon and dust to both snow and sea ice. For these purposes we employ a slab ocean version of CESM1, using the Community Atmosphere Model version 4 (CAM4), run to equilibrium for year 2000 levels of CO 2 and fixed aerosol deposition. We construct experiments with and without aerosol deposition, with dust or black carbon deposition alone, and with varying quantities of black carbon and dust to approximate year 1850 and 2000 deposition fluxes. The year 2000 deposition fluxes of both dust and black carbon cause 1-2 • C of surface warming over large areas of the Arctic Ocean and subArctic seas in autumn and winter and in patches of Northern land in every season. Atmospheric circulation changes are a key component of the surface-warming pattern. Arctic sea ice thins by on average about 30 cm. Simulations with year 1850 aerosol deposition are not substantially different from those with year 2000 deposition, given constant levels of CO 2 . The climatic impact of particulate impurities deposited over land exceeds that of particles deposited over sea ice. Even the surface warming over the sea ice and sea ice thinning depends more upon light-absorbing particles deposited over land. For CO 2 doubled relative to year 2000 levels, the climate impact of particulate impurities in snow and sea ice is substantially lower than for the year 2000 equilibrium simulation.

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“…Russell et al (1999) and Redemann et al (2000) have used such properties for estimating the ADRF in the TARFOX study. Quijano et al (2000) used t; o and g spectra of mineral dusts in Saharan and the Afhgan desert area using the refractive index measurement of Patterson (1981), which show rather smooth variations with respect to wavelength in the short wave regime, but not in the IR regime. Similar patterns are identified for marine aerosols (Smirnov et al 1995) and biomass burning aerosol ).…”

Section: Introductionmentioning

confidence: 99%

Estimation of Direct Radiative Forcing of Asian Dust Aerosols with Sun/Sky Radiometer and Lidar Measurements at Gosan, Korea

Won

Yoon

Kim

et al. 2004

Journal of the Meteorological Society of Japan

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In this study the aerosol direct radiative forcing (ADRF) of Asian dust is evaluated by model simulation at Gosan, Jeju using the data from a sun/sky radiometer, a Micro-Pulse Lidar (MPL), and column radiometer measurements of solar downwelling irradiance in April, 2001. We suggest a method of determining aerosol parameters for the radiative transfer model from the Aerosol Robotic Network (AERONET) data set. Since the AERONET measurements provide the refractive indices at only four wavelengths, and the aerosol parameters can be calculated at these wavelengths with a Mie code, we use a linear regression method for extending these measurements to the full wavelength spectrum of the radiative transfer model.The aerosol forcing by the Asian dust aerosols is estimated and compared to the aerosol forcing of non-dust aerosols. On the Asian dust event day, April 13, the daily average ADRF was estimated as À58.1 W/m 2 at the surface and À25.7 W/m 2 at the top of the atmosphere (TOA). On April 15, a nondust day slightly influenced by anthropogenic aerosols, the ADRF was À29.0 W/m 2 at the surface and À11.6 W/m 2 at the TOA. Although the Asian dust aerosols show larger forcing, its forcing efficiency (forcing per unit optical thickness) is smaller than that of non-dust aerosols; À41.0 W/m 2 /t 670 at the TOA and À94.9 W/m 2 /t 670 at the surface on the dust day for dust aerosols, as opposed to À50.0 W/m 2 /t 670 at the TOA and À129.3 W/m 2 /t 670 at the surface on the non-dust day for non-dust aerosols. We believe that this is due to the larger single scattering albedo of dust aerosols, which causes smaller absorption, and the larger asymmetry factor which causes more forward scattering or less reflection, compared to anthropogenic aerosols.The model results were validated with the surface irradiance measurement data and the comparison showed a good agreement. The radiative transfer calculation underestimates the solar irradiance of 2@3% on average. The aerosol profiles measured by lidar are used to estimate the influence of the vertical distribution of Asian dust aerosols on the ADRF. Using the vertical aerosol profiles, we found an Corresponding author: Jae-Gwang Won, School of Earth and Environmental Sciences, Seoul National University, Seoul 151-747, Korea. E-mail: wonjg@air.snu.ac.kr ( 2004, Meteorological Society of Japan instantaneous short wave radiative heating larger than 2 K/day. We believe the enhanced heating rate by the aerosol layers contributes to the increase in static stability within the dust layer. This fact is verified by the temperature profile measured by the sonde, and may explain the longevity and consequently long-range transport of Asian dust.

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Optical properties of the crustal aerosol: Relation to chemical and physical characteristics

Cited by 95 publications

References 49 publications

Columnar aerosol single‐scattering albedo and phase function retrieved from sky radiance over the ocean: Measurements of Saharan dust

Columnar aerosol single‐scattering albedo and phase function retrieved from sky radiance over the ocean: Measurements of Saharan dust

Arctic climate response to forcing from light-absorbing particles in snow and sea ice in CESM

Estimation of Direct Radiative Forcing of Asian Dust Aerosols with Sun/Sky Radiometer and Lidar Measurements at Gosan, Korea

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