Intercomparison of satellite retrieved aerosol optical depth over ocean during the period September 1997 to December 2000 G. Myhre1,2, F. Stordal1,2, M. Johnsrud1, D. J. Diner3, I. V. Geogdzhayev4, J. M. Haywood5, B. N. Holben6, T. Holzer-Popp7, A. Ignatov8, R. A. Kahn3, Y. J. Kaufman9, N. Loeb10, J. V. Martonchik3, M. I. Mishchenko4, N. R. Nalli8, L. A. Remer9, M. Schroedter-Homscheidt7, D. Tanré11, O. Torres12, and M. Wang13 1Norwegian Institute for Air Research (NILU), Kjeller, Norwayp 2Department of Geosciences, University of Oslo, Oslo, Norway 3Jet Propulsion Laboratory, California Institute of Technology, Pasadena California, USA 4NASA Goddard Institute for Space Studies, New York, New York, USA 5Met Office, Exeter, UK 6Biospheric Sciences Branch, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA 7Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Deutsches Fernerkundungsdatenzentrum (DFD), Oberpfaffenhofen, Germany 8NOAA/NESDIS/Office of Research and Applications/Climate Research and Applications Division, Washington, D.C., USA 9Laboratory for Atmospheres, NASA/Goddard Space Flight Center, Greenbelt, Maryland, USA 10Center for Atmospheric Sciences, Hampton University, Hampton, VA., USA 11Laboratoire d’Optique Atmosphérique, Université de Lille/CNRS, Villeneuve d’Ascq, France 12Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, Maryland, USA 13University of Maryland-Baltimore County, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Abstract. Monthly mean aerosol optical depth (AOD) over ocean is compared from a total
of 9 aerosol retrievals during a 40 months period. Comparisons of AOD have
been made both for the entire period and sub periods. We identify regions
where there is large disagreement and good agreement between the aerosol
satellite retrievals. Significant differences in AOD have been identified in
most of the oceanic regions. Several analyses are performed including
spatial correlation between the retrievals as well as comparison with
AERONET data. During the 40 months period studied there have been several
major aerosol field campaigns as well as events of high aerosol content. It
is studied how the aerosol retrievals compare during such circumstances. The
differences found in this study are larger than found in a previous study
where 5 aerosol retrievals over an 8 months period were compared. Part of
the differences can be explained by limitations and deficiencies in some of
the aerosol retrievals. In particular, results in coastal regions are
promising especially for aerosol retrievals from satellite instruments
particularly suited for aerosol research. In depth analyses explaining the
differences between AOD obtained in different retrievals are clearly needed.
We limit this study to identifying differences and similarities and
indicating possible sources that affect the quality of the retrievals. This
is a necessary first step towards understanding the differences and
improving the retrievals.
Citation: Myhre, G., Stordal, F., Johnsrud, M., Diner, D. J., Geogdzhayev, I. V., Haywood, J. M., Holben, B. N., Holzer-Popp, T., Ignatov, A., Kahn, R. A., Kaufman, Y. J., Loeb, N., Martonchik, J. V., Mishchenko, M. I., Nalli, N. R., Remer, L. A., Schroedter-Homscheidt, M., Tanré, D., Torres, O., and Wang, M.: Intercomparison of satellite retrieved aerosol optical depth over ocean during the period September 1997 to December 2000, Atmos. Chem. Phys., 5, 1697-1719, doi:10.5194/acp-5-1697-2005, 2005.