Estimation of a "radiatively correct" black carbon specific absorption during the Mexico City Metropolitan Area (MCMA) 2003 field campaign
Open Access
- 27 March 2007
- journal article
- Published by Copernicus GmbH in Atmospheric Chemistry and Physics
- Vol. 7 (6), 1645-1655
- https://doi.org/10.5194/acp-7-1645-2007
Abstract
During the Mexico City Metropolitan Area (MCMA) field campaign of 2003, measurements of the shortwave radiation field allowed the inference of the black carbon (BC) specific absorption, αλ, defined as the monochromatic absorption cross section per unit mass (with units of m2/g). The averaged values of αλ derived from the method here are either 8.9 m2/g or 8.2 m2/g at 500 nm, depending upon the physical and optical parameters assumed for BC. These results are reasonably consistent with those of Schuster et al. (2005), 9.5 m2/g, and Baumgartner et al. (2002), 7.0 m2/g, both measured at 550 nm. The αλ values reported in this paper should only be considered effective, "radiatively correct" values because when used in radiative transfer calculations the calculated irradiances match the measured irradiances at 500 nm. The specific absorption so defined can assume a wide range of values, depending upon: (1) the assumptions made prior to the retrieval (e.g., shell/core aerosol configuration), and (2) values chosen for BC density and refractive index. The range of possible values is large, corresponding to a "worst case" uncertainty of about ±70%, assuming that all errors are additive and of the same sign so that no error cancellation occurs.Keywords
This publication has 46 references indexed in Scilit:
- Limitations in the enhancement of visible light absorption due to mixing stateJournal of Geophysical Research: Solid Earth, 2006
- Light Absorption by Carbonaceous Particles: An Investigative ReviewAerosol Science and Technology, 2006
- Photoacoustic and filter‐based ambient aerosol light absorption measurements: Instrument comparisons and the role of relative humidityJournal of Geophysical Research: Solid Earth, 2003
- Global distribution and climate forcing of carbonaceous aerosolsJournal of Geophysical Research: Solid Earth, 2002
- Diagnosing black carbon trends in large urban areas using carbon monoxide measurementsJournal of Geophysical Research: Solid Earth, 2002
- Wavelength Dependence of the Absorption of Black Carbon Particles: Predictions and Results from the TARFOX Experiment and Implications for the Aerosol Single Scattering AlbedoJournal of the Atmospheric Sciences, 2002
- On the evolution of aerosol properties at a mountain site above Mexico CityJournal of Geophysical Research: Solid Earth, 2000
- A flexible inversion algorithm for retrieval of aerosol optical properties from Sun and sky radiance measurementsJournal of Geophysical Research: Solid Earth, 2000
- Effect of black carbon on the optical properties and climate forcing of sulfate aerosolsJournal of Geophysical Research: Solid Earth, 1995
- Absorption of visible radiation in atmosphere containing mixtures of absorbing and nonabsorbing particlesApplied Optics, 1981