Intercomparison of satellite retrieved aerosol optical depth over ocean during the period September 1997 to December 2000

Abstract

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. However, results in coastal regions are promising especially for aerosol retrievals from satellite instruments dedicated for aerosol research. In depth analyses explaining the differences between AOD obtained in different retrievals are clearly needed. We limit this study to identify differences and similarities and indicate possible sources that affect the quality of the retrievals. This is a necessary first step towards understanding the differences and improving the retrievals.

Aerosol variability in the Adriatic Sea from automated optical field measurements and Sea‐viewing Wide Field‐of‐view Sensor (SeaWiFS)

“…To ensure good quality of the retrievals for atmospheric and marine products resulting from the atmospheric correction scheme (see Mélin et al [2003, 2005] for validation results in terms of water leaving radiance), the cloud screening, based on a threshold for the top‐of‐atmosphere reflectance at 865 nm, is quite stringent and filters out pixels of high aerosol load (haze or thick desert dust). This limitation has been mentioned by other authors for aerosol products obtained with the standard SeaWiFS atmospheric correction [e.g., Chou et al , 2002; Myhre et al , 2005]. The issues of cloud screening and spatial/temporal sampling have also been discussed in the context of comparison involving satellite products, surface values or dynamic models outputs [e.g., Kinne et al 2003; Geogdzhayev et al , 2004; Myhre et al , 2004; Jeong and Li , 2005].…”

Study of the Sea‐Viewing Wide Field‐of‐View Sensor (SeaWiFS) aerosol optical property data over ocean in combination with the ocean color products

“…The detailed comparisons and analyses of the satellite‐derived AOT over ocean from total of nine aerosol retrieval algorithms, which includes algorithms for data measured by AVHRR, TOMS, SeaWiFS, MODIS, MISR, and some other sensors, have been carried out by Myhre et al [2005]. In that study, the satellite results are also compared with the ground‐based data from AERONET [ Holben et al , 1998].…”

“…In that study, the satellite results are also compared with the ground‐based data from AERONET [ Holben et al , 1998]. Although some good agreements are found within various satellite data products, significant differences in the derived AOT from various satellite sensors, in particular, at the high latitude regions (e.g., southern oceans), are reported [ Myhre et al , 2005]. This is true even for sensors dedicated for the aerosol measurements.…”

“…This is true even for sensors dedicated for the aerosol measurements. In general, for cases with not too large AOT, the SeaWiFS AOT is compared well with the AERONET ground‐based measurements and with results derived from some of sensors (e.g., AVHRR, MODIS) [ Myhre et al , 2005]. SeaWiFS aerosol product shows high stability and usually has the lowest data variation (standard deviation) in all the data sets.…”

Satellite‐derived aerosol optical depth over dark water from MISR and MODIS: Comparisons with AERONET and implications for climatological studies

“…The Multiangle Imaging Spectroradiometer (MISR) [ Diner et al , 1998] began taking data in late February 2000. Since then, numerous studies have compared aerosol optical thickness (AOT) retrieved from the instrument's 36 spectral angular channels with similar quantities derived from the Aerosol Robotic Network (AERONET) [ Holben et al , 1998] Sun photometer network, the Moderate Resolution Imaging Spectroradiometer (MODIS) [ Barnes et al , 1998; Salomonson et al , 1989] that flies aboard the Terra satellite with MISR, and other regional and global observations [e.g., Abdou et al , 2005; Christopher and Wang , 2004; Diner et al , 2001; Kahn et al , 2005a, 2005b; Liu et al , 2004; Martonchik et al , 2004; Myhre et al , 2005; Redemann et al , 2005; Schmid et al , 2003; Yu et al , 2006]. That work demonstrates the MISR Standard Aerosol Retrieval algorithm (V16 or lower) retrieves AOT over land and water, with overall statistical accuracy better than 0.05 or 20%, whichever is larger, and with greater accuracy over some surfaces such as dark water.…”