References

ACPD

Atmospheric Chemistry and Physics Discussions

ACPD

1680-7375

Copernicus GmbH

Göttingen, Germany

10.5194/acpd-9-27543-2009

Aerosol spectral absorption in the Mexico City area: results from airborne measurements during MILAGRO/INTEX B

Bergstrom

R. W.

¹ Schmidt

K. S.

² Coddington

² Pilewskie

² Guan

¹ Livingston

J. M.

³ Redemann

¹ Russell

P. B.

⁴

Bay Area Environmental Research Institute, Sonoma, CA, USA

Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA

SRI International, Menlo Park, CA, USA

NASA Ames Research Center, Moffett Field, CA, USA

21 12 2009

9 6 27543 27569

This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

This article is available from http://www.atmos-chem-phys-discuss.net/9/27543/2009/acpd-9-27543-2009.html

The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/9/27543/2009/acpd-9-27543-2009.pdf

This paper presents estimates of the spectral solar absorption due to atmospheric aerosols during the 2006 MILAGRO/INTEX-B (Megacity Initiative-Local And Global Research Observations/Phase B of the Intercontinental Chemical Transport Experiment) field campaign. The aerosol absorption was derived from measurements of the spectral solar radiation and the spectral aerosol optical depth made on the J31 aircraft flying over the Gulf of Mexico and over Mexico City. We present the spectral single scattering albedo (SSA) and aerosol absorption optical depth (AAOD) for two flights over the Gulf of Mexico and three flights over Mexico City for wavelengths from 350 to approximately 1650 nm. The spectral aerosol optical properties of each case are different and illustrate the variability of the aerosol optical properties in the Mexico City area. The results can be described in terms of three different wavelength region: The 350–500 nm region where the aerosol absorption often falls off sharply presumably due to organic carbonaceous particles and windblown dust; the 500–1000 nm region where the decrease with wavelength is slower presumably due to black carbon; and the near infrared spectral region (1000 nm to 1650 nm) where it is difficult to obtain reliable results since the aerosol absorption is relatively small and the gas absorption dominates. However, there is an indication of a small and somewhat wavelength independent absorption in the region beyond 1000 nm. For one of the flights over the Gulf of Mexico near the coastline it appears that a cloud/fog formation and evaporation led to an increase of absorption possibly due to a water shell remaining on the particles after the cloud/fog had dissipated. For two of the Mexico City cases, the single scattering albedo is roughly constant between 350–500 nm consistent with other Mexico City results. In three of the cases a single absorption Angstrom exponent (AAE) fits the aerosol absorption optical depth over the entire wavelength range of 350 to 1650 nm relatively well (r2>0.86).

References 1

Adachi, K. and Buseck, P. R.: Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City, Atmos. Chem. Phys., 8, 6469–6481, 2008.

Barnard, J. C., Volkamer, R., and Kassianov, E. I.: Estimation of the mass absorption cross section of the organic carbon component of aerosols in the Mexico City Metropolitan Area, Atmos. Chem. Phys., 8, 6665–6679, 2008.

Bergstrom, R. W., Pilewskie, P., Schmid, B., and Russell, P. B.: Estimates of the spectral aerosol single scattering albedo and aerosol radiative effects during SAFARI~2000, J. Geophys. Res., 108(D13), 8474, doi:10.1029/2002JD002435, 2003.

Bergstrom, R. W., Pilewskie, P., Pommier, J., Rabbette, M., Russell, P. B., Schmid, B., Redemann, J., Higurashi, A., Nakajima, T., and Quinn, P. K.: Spectral absorption of solar radiation by aerosols during ACE-Asia, J. Geophys. Res., 109, D19S15, doi:10.1029/2003JD004467, 2004.

Bergstrom, R. W., Pilewskie, P., Russell, P. B., Redemann, J., Bond, T. C., Quinn, P. K., and Sierau, B.: Spectral absorption properties of atmospheric aerosols, Atmos. Chem. Phys., 7, 5937–5943, 2007.

Bond, T. C., Habib, G., and Bergstrom, R. W.: Limitations in the enhancement of visible light absorption due to mixing state, J. Geophys. Res., 111, D20211, doi:10.1029/2006JD007315, 2006.

Chandrasekhar, S.: Radiative Transfer, New York: Dover, 393~p., 1960.

Chen, Y. and Bond, T. C.: Light absorption by organic carbon from wood combustion, Atmos. Chem. Phys. Discuss., 9, 20471–20513, 2009.

Coddington, O., Schmidt, K. S., Pilewskie, P., Gore, W. J., Bergstrom, R. W., Román, M. O., Redemann, J., Russell, P. B., Liu, J., and Schaaf, C. B.: Examining the impact of overlying aerosols on the retrieval of cloud optical properties from passive remote sensing, J. Geophys. Res., doi:10.1029/2008JD010089, accepted on 14~December~2009, 2008.

Coddington, O.: The application of airborne shortwave spectral irradiance measurements to atmosphere and surface remote sensing, Phd~Thesis, University of Colorado, 2009a.

Coddington, O., Schmidt, K. S., Pilewskie, P., Gore, W. J., Bergstrom, R. W., Román, M., Redemann, J., Russell, P. B., Liu, J., and Schaaf, C. C.: Aircraft measurements of spectral surface albedo and its consistency with ground-based and space-borne observations, J. Geophys. Res., 113, D17209, doi:10.1029/2008JD010089, 2008.

Corr, C. A., Krotkov, N., Madronich, S., Slusser, J. R., Holben, B., Gao, W., Flynn, J., Lefer, B., and Kreidenweis, S. M.: Retrieval of aerosol single scattering albedo at ultraviolet wavelengths at the T1 site during MILAGRO, Atmos. Chem. Phys., 9, 5813–5827, 2009.

IPCC, 2007: Climate Change 2007: The Physical Science Basis, Contribution of Working Group~I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L., Cambridge University Press, Cambridge, UK and New York, NY, USA, 2007.

Jeong, G. N. and Sokolik, I. N.: Effect of mineral dust aerosols on the photolysis rates in the clean and polluted marine environments, J. Geophys. Res., 112, D21308, doi:10.1029/2007JD008442, 2007.

Kirchstetter, T. W., Novakov, T., and Hobbs, P.: Evidence that the spectral dependence of light absorption by aerosols is affected by organic carbon, J. Geophys. Res., 109, D21208, doi:10.1029/2004JD004999, 2004.

Kurucz, R. L.: The solar spectrum: atlases and line identifications. Presented at the Workshop on Laboratory and Astronomical High Resolution Spectra, 29~August–2~September~1994, Brussels, in: Laboratory and Astronomical High Resolution Spectra, Astron. Soc. of the Pacific Conf. Series~81, edited by: Sauval, A. J., Blomme, R., and Grevesse, N., San Francisco, Astron. Soc. of the Pacific, 17–31~pp., 1995.

Livingston, J. M., Redemann, J., Russell, P. B., Torres, O., Veihelmann, B., Veefkind, P., Braak, R., Smirnov, A., Remer, L., Bergstrom, R. W., Coddington, O., Schmidt, K. S., Pilewskie, P., Johnson, R., and Zhang, Q.: Comparison of aerosol optical depths from the Ozone Monitoring Instrument (OMI) on Aura with results from airborne sunphotometry, other space and ground measurements during MILAGRO/INTEX-B, Atmos. Chem. Phys., 9, 6743–6765, 2009.

Marley, N. A., Gaffney, J. S., Castro, T., Salcido, A., and Frederick, J.: Measurements of aerosol absorption and scattering in the Mexico City Metropolitan Area during the MILAGRO field campaign: a comparison of results from the T0 and T1 sites, Atmos. Chem. Phys., 9, 189–206, 2009.

Marley, N. A., Gaffney, J. S., Tackett, M., Sturchio, N. C., Heraty, L., Martinez, N., Hardy, K. D., Marchany-Rivera, A., Guilderson, T., MacMillan, A., and Steelman, K.: The impact of biogenic carbon sources on aerosol absorption in Mexico City, Atmos. Chem. Phys., 9, 1537–1549, 2009.

Martins, J. V., Artaxo, P., Kaufman, Y. J., Castanho, A. D., and Remer, L. A.: Spectral absorption properties of aerosol particles from 350–2500 nm, Geophys. Res. Lett., 36, L13810, doi:10.1029/2009GL037435, 2009.

Mielonen, T., Arola, A., Komppula, M., Kukkonen, J., Koskinen, J., de Leeuw, G., and Lehtinen, K. E. J.: Comparison of CALIOP level~2 aerosol subtypes to aerosol types derived from AERONET inversion data, Geophys. Res. Lett., 36, L18804, doi:10.1029/2009GL039609, 2009.

Molina, L. T., Madronich, S., Gaffney, J., et al.: An Overview of MILAGRO~2006 Campaign: Mexico City Emissions and its Transport and Transformation, submitted to Atmos. Chem. Phys. Discuss., 2009.

Redemann, J., Russell, P. B., and Hamill, P.: Dependence of aerosol light absorption and single scattering albedo on ambient relative humidity for sulfate aerosols with black carbon cores, J. Geophys. Res., 106, 27485–27495, 2001.

Redemann, J., Zhang, Q., Livingston, J., Russell, P., Shinozuka, Y., Clarke, A., Johnson, R., and Levy, R.: Testing aerosol properties in MODIS Collection~4 and 5 using airborne sunphotometer observations in INTEX-B/MILAGRO, Atmos. Chem. Phys., 9, 8159–8172, 2009.

Russell, P. B., Livingston, J. M., Redemann, J., Schmid, B., Ramirez, S. A., Eilers, J., Khan, R., Chu, A., Remer, L., Quinn, P. K., Rood, M. J., and Wang, W.: Multi-Grid-Cell Validation of Satellite Aerosol Property Retrievals in INTEX/ITCT/ICARTT~2004, J. Geophys. Res., 112, D12S09, doi:10.1029/2006JD007606, 2007.

Russell, P. B., Bergstrom, R. W., Shinozuka, Y., Clarke, A. D., DeCarlo, P. F., Jimenez, J. L., Livingston, J. M., Redemann, J., Holben, B., Dubovik, O., and Strawa, A.: Absorption Angstrom Exponent in AERONET and related data as an indicator of aerosol composition, Atmos. Chem. Phys. Discuss., 9, 21785–21817, 2009.

Schmidt, K. S., Pilewskie, P., Bergstrom, R., Bierwirth, E., Coddington, O., Redemann, J., Livingston, J., Russel, P., Wendisch, M., and Gore, W.: Aerosol radiative properties from airborne measurements over ocean and land during MILAGRO, in preparation, 2009.

Schwarz, J. P., Spackman, J. R., Fahey, D. W., et al.: Coatings and their enhancement of black carbon light absorption in the tropical atmosphere, J. Geophys. Res., 113, D03203, doi:10.1029/2007JD009042, 2008.

Shinozuka, Y., Clarke, A. D., DeCarlo, P. F., Jimenez, J. L., Dunlea, E. J., Roberts, G. C., Tomlinson, J. M., Collins, D. R., Howell, S. G., Kapustin, V. N., McNaughton, C. S., and Zhou, J.: Aerosol optical properties relevant to regional remote sensing of CCN activity and links to their organic mass fraction: airborne observations over Central Mexico and the US West Coast during MILAGRO/INTEX-B, Atmos. Chem. Phys., 9, 6727–6742, 2009.

Yang, M., Howell, S. G., Zhuang, J., and Huebert, B. J.: Attribution of aerosol light absorption to black carbon, brown carbon, and dust in China - interpretations of atmospheric measurements during EAST-AIRE, Atmos. Chem. Phys., 9, 2035–2050, 2009.