Atmospheric Chemistry and Physics Discussions
www.atmos-chem-phys-discuss.net
1680-7367
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6
6
2006
10.5194/acpd-6-13367-2006
http://www.atmos-chem-phys-discuss.net/6/13367/2006/
http://www.atmos-chem-phys-discuss.net/6/13367/2006/acpd-6-13367-2006.html
http://www.atmos-chem-phys-discuss.net/6/13367/2006/acpd-6-13367-2006.pdf
13367
13386
2006-12-21
Aerosol single-scattering albedo and asymmetry parameter from MFRSR observations during the ARM Aerosol IOP 2003
E. I. Kassianov
debbie.ronfeld@pnl.gov
T. P. Ackerman
J. C. Barnard
C. J. Flynn
Pacific Northwest National Laboratory P.O. Box 999 Richland, WA 99352, USA
Multi-filter Rotating Shadowband Radiometers (MFRSRs) provide routine
measurements of the aerosol optical depth (τ) at six wavelengths
(0.415, 0.5, 0.615, 0.673, 0.870 and 0.94 μm). The single-scattering
albedo (ϖ<sub>0</sub>) is typically estimated from the MFRSR measurements by
assuming the asymmetry parameter (<i>g</i>). In most instances, however, it is
not easy to set an appropriate value of <i>g</i> due to its strong temporal and
spatial variability. Here, we introduce and validate an updated version of
our retrieval technique that allows one to estimate simultaneously ϖ<sub>0</sub>
and <i>g</i> for different types of aerosol. We use the aerosol and radiative
properties obtained during the Atmospheric Radiation Measurement (ARM)
Aerosol Intensive Operational Period (IOP) to validate our retrieval in two
ways. First, the MFRSR-retrieved optical properties are compared with those
obtained from independent surface, Aerosol Robotic Network (AERONET) and
aircraft measurements. The MFRSR-retrieved optical properties are in
reasonable agreement with these independent measurements. Second, we perform
radiative closure experiments using the MFRSR-retrieved optical properties.
The calculated broadband values of the direct and diffuse fluxes are
comparable (~5 <i>W/m</i><sup>2</sup>) to those obtained from measurements.
Alexandrov M D., Lacis, A A., Carlson, B E., and Cairns, B.: Remote sensing of atmospheric aerosols and trace gases by means of multifilter rotating shadowband radiometer. Part I: Retrieval algorithm, J. Atmos. Sci., 59, 524–543, 2002.
Andrews, E., Sheridan P., Fiebig, M., McComiskey, A., Ogren, J., Arnott, P., Covert, D., Elleman, R., Gasparini, R., Collins, D., Jonsson, H., Schmid, B., and Wang, J.: Comparison of methods for deriving aerosol asymmetry parameter, J. Geophys. Res., 111, D05S04, doi:10.1029/2004JD005734, 2006.
Andrews, E., Sheridan, P. J., Ogren, J. A., and Ferrare, R.: In situ aerosol profiles over the Southern Great Plains cloud and radiation test bed site: 1. Aerosol optical properties, J. Geophys. Res., 109, D06208, doi:10.1029/2003JD004025, 2004.
Barnard, J. C. and Powell, D. M.: A Comparison Between Modeled and Measured Clear Sky Radiative Shortwave Fluxes in Arctic Environments – With Special Emphasis on Diffuse Radiation, J. Geophys. Res., 107, 4383, doi:10.1029/2001JD001442, 2002.
Dubovik, O., Holben, B., Eck, T. F., Smirnov, A., Kaufman, Y., King, M., Tanre, D., and Slutsker, I.: Variability of absorption and optical properties of key aerosol types observed in worldwide locations, J. Atmos. Sci., 59, 590–608, 2002.
Gonzalez-Jorge, H. G. and Ogren, J. A.: Sensitivity of retrieved aerosol properties to assumptions in the inversion of spectral optical depth, J. Atmos. Sci., 53, 3669–3683, 1996.
Halthore, R., Nemesure, S., Schwartz, S. E., Imre, D. G., Berk, A., Dutton, E. G., and Bergin, M.: Models overestimate diffuse clear-sky irradiance: A case for excess atmospheric absorption, Geophys. Res. Lett., 25, 3591–3594, 1998.
Halthore, R., Miller, M., Orgen, J., Sheridan, P., Slater, D., and Stoffel, T.: Further developments in closure experiments for surface diffuse irradiance under cloud-free skies at a continental site, Geophys. Res. Lett., 31, L07111, doi:10.1029/2003GL019102, 2004.
Hansen, J. E., Sato, M., and Ruedy, R.: Radiative forcing and climate response, J. Geophys. Res., 102, 6831–6864, 1997.
Harrison, L. and Michalsky, J.: Objective algorithms for the retrieval of optical depths from ground-based measurements, J. Appl. Opt., 22, 5126–5132, 1994.
Haywood, J. and Shine, K.: The effect of anthropogenic sulfate and soot aerosol on the clear sky planetary radiation budget, J. Geophys. Res. Lett., 22, 603–606, 1995.
Holben, B., Eck, T. F., Slutsker, I., Tanre, D., Buis, J. P., Setzer, A., Vermote, E., Reagan, J. A., Kaufman, Y. J., Nakajima, T., Lavenu, F., Jankowiak, I., and Smirnov, A.: A federated instrument network and data archive for aerosol characterization, Remote Sens. Environ., 66, 1–16, 1998.
Kassianov, E I., Barnard, J C., and Ackerman, T P.: Retrieval of aerosol microphysical properties by using surface MFRSR data: Modeling and observations, J. Geophys. Res., 110, D09201, doi:10.1029/2004JD005337, 2005.
Kato, S., Ackerman, T. P., Clothiaux, E. E., Mather, J. H., Mace, G. G., Wesely, M. L., Murcray, F., and Michalsky, J.: Uncertainties in modeled and measured clear-sky surface shortwave irradiances, J. Geophys. Res., 102, 25 881–25 898, 1997.
Long, C N. and Ackerman, T P.: Identification of clear skies from broadband pyranometer measurements and calculation of downwelling shortwave cloud effects, J. Geophys. Res., 105, 15 609–15 626, 2000.
Meloni, D., di Sarra, A., Pace, G., and Monteleone, F.: Aerosol optical properties at Lampedusa (Central Mediterranean) -2. Determination of single scattering albedo at two wavelengths for different aerosol types, Atmos. Chem. Phys. Discuss., 5, 4971–5005, 2005.
Michalsky, J. J., Schlemmer, J. A., Berkheiser, W. E., Berndt, J. L., Harrison, L. C., Laulainen, N. S., Larson, N. R., and Barnard, J.: Multiyear measurements of aerosol optical depth in the Atmospheric Radiation Measurement and Quantitative Links programs, J. Geophys. Res., 106, 12 099–12 107, 2001.
Michalsky, J. J., Anderson, G. P., Barnard, J., Delamere, J., Gueymard, C., Kato, S., Kiedron, P., McComiskey, A., and Ricchiazzi, P.: Shortwave radiative closure studies for clear skies during the Atmospheric Radiation Measurement 2003 Aerosol Intensive Observation Period, J. Geophys. Res., 111, D14S90, doi:10.1029/2005JD006341, 2006.
Petters, J L., Saxena, V K., Slusser, J R., Wenny, B N., and Madronich, S.: Aerosol single scattering albedo retrieved from measurements of surface UV irradiance and a radiative transfer model, J. Geophys. Res., 108(D9), 4288, doi:10.1029/2002JD002360, 2003.
Ricchiazzi, P., Gautier, C., Ogren, J., and Schmid, B.: A comparison of aerosol optical properties obtained from in situ measurements and retrieved from Sun and sky radiance observations during the May 2003 ARM Aerosol Intensive Observational Period, J. Geophys. Res., 111, D05S06, doi:10.1029/2005JD005863, 2006.
Russell, P., Kinne, S., and Bergstrom, R.: Aerosol climate effects: Local radiative forcing and column closure experiments. J. Geophys. Res., 102, 9397–9407, 1997.
Sheridan, P., Delene, D., and Orgen, J.: Four years of continuous surface aerosol measurements from the Department of Energy's Atmospheric Radiation Measurement Program Southern Great Plains Cloud and Radiation Testbed site, J. Geophys. Res., 106, 20 735–20 747, 2001.
Slingo, A, Ackerman, T., Allan, R., Kassianov, E., McFarlane, S., Robinson, G., Barnard, J., Miller, M., Harries, J., Russell, J., and Dewitte, S.: Observations of the impact of a major Saharan dust storm on the Earth's radiation budget, J. Geophys. Res. Lett., in press, 2006.
Wiscombe, W. and Grams, G.: The backscattering fraction in two-stream approximations, J. Atmos. Sci., 33, 2440–2451, 1976.
Zhang, J. and Christopher, S.: Shortwave aerosol radiative forcing over cloud-free oceans from Terra: 2. Seasonal and global distributions, J. Geophys. Res., 110(D10S24), doi:10.1029/2004JD005009, 2005.